diff --git a/Makefile.in b/Makefile.in
index 96e199b60b..6e01ccd1c5 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -281,7 +281,6 @@ am__aclocal_m4_deps = $(top_srcdir)/m4/ac_func_fseeko.m4 \
 	$(top_srcdir)/m4/ax_prog_perl_version.m4 \
 	$(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/ax_require_defined.m4 \
-	$(top_srcdir)/m4/cxx_have_std_libs.m4 \
 	$(top_srcdir)/m4/framework.m4 \
 	$(top_srcdir)/m4/ld-version-script.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltoptions.m4 \
@@ -3242,6 +3241,7 @@ PRTDIAG = @PRTDIAG@
 PSDelegate = @PSDelegate@
 PTHREAD_CC = @PTHREAD_CC@
 PTHREAD_CFLAGS = @PTHREAD_CFLAGS@
+PTHREAD_CXX = @PTHREAD_CXX@
 PTHREAD_LIBS = @PTHREAD_LIBS@
 PrintDelegate = @PrintDelegate@
 QUANTUM_DEPTH = @QUANTUM_DEPTH@
diff --git a/aclocal.m4 b/aclocal.m4
index eb03b7d8ef..10de731ae6 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1285,7 +1285,6 @@ m4_include([m4/ax_prepend_flag.m4])
 m4_include([m4/ax_prog_perl_version.m4])
 m4_include([m4/ax_pthread.m4])
 m4_include([m4/ax_require_defined.m4])
-m4_include([m4/cxx_have_std_libs.m4])
 m4_include([m4/framework.m4])
 m4_include([m4/ld-version-script.m4])
 m4_include([m4/libtool.m4])
diff --git a/config/config.h.in b/config/config.h.in
index 4b821f647d..3c53c27cf5 100644
--- a/config/config.h.in
+++ b/config/config.h.in
@@ -272,9 +272,6 @@
 /* Define to 1 if you have the <limits.h> header file. */
 #undef HAVE_LIMITS_H
 
-/* Define if you have Linux-compatible sendfile() */
-#undef HAVE_LINUX_SENDFILE
-
 /* Define to 1 if you have the <linux/unistd.h> header file. */
 #undef HAVE_LINUX_UNISTD_H
 
@@ -475,9 +472,6 @@
 /* Define to 1 if you have the <stdlib.h> header file. */
 #undef HAVE_STDLIB_H
 
-/* define if the compiler supports ISO C++ standard library */
-#undef HAVE_STD_LIBS
-
 /* Define to 1 if you have the `strcasecmp' function. */
 #undef HAVE_STRCASECMP
 
@@ -951,10 +945,6 @@
 /* Define if you have TIFF library */
 #undef TIFF_DELEGATE
 
-/* Define to 1 if you can safely include both <sys/time.h> and <time.h>. This
-   macro is obsolete. */
-#undef TIME_WITH_SYS_TIME
-
 /* Define to 1 if your <sys/time.h> declares `struct tm'. */
 #undef TM_IN_SYS_TIME
 
@@ -1127,9 +1117,6 @@
 # undef __CHAR_UNSIGNED__
 #endif
 
-/* Define to appropriate substitute if compiler does not have __func__ */
-#undef __func__
-
 /* Define to empty if `const' does not conform to ANSI C. */
 #undef const
 
diff --git a/configure b/configure
index 625dee8067..b331150bff 100755
--- a/configure
+++ b/configure
@@ -992,6 +992,7 @@ OPENMP_CFLAGS
 THREAD_LIBS
 PTHREAD_CFLAGS
 PTHREAD_LIBS
+PTHREAD_CXX
 PTHREAD_CC
 ax_pthread_config
 pkgconfigdir
@@ -4000,7 +4001,6 @@ main (int argc, char **argv)
 }
 "
 
-as_fn_append ac_header_c_list " sys/time.h sys_time_h HAVE_SYS_TIME_H"
 as_fn_append ac_header_c_list " sys/param.h sys_param_h HAVE_SYS_PARAM_H"
 as_fn_append ac_func_c_list " getpagesize HAVE_GETPAGESIZE"
 as_fn_append ac_header_c_list " vfork.h vfork_h HAVE_VFORK_H"
@@ -4304,8 +4304,6 @@ test -n "$target_alias" &&
     NONENONEs,x,x, &&
   program_prefix=${target_alias}-
 
-
-
 am__api_version='1.16'
 
 
@@ -5127,7 +5125,7 @@ MAGICK_PATCHLEVEL_VERSION=49
 
 MAGICK_VERSION=6.9.12-49
 
-MAGICK_GIT_REVISION=21ffed7d9:20220510
+MAGICK_GIT_REVISION=281f3b20c:20220511
 
 
 # Substitute library versioning
@@ -5161,7 +5159,7 @@ PACKAGE_LIB_VERSION=0x69C
 
 PACKAGE_LIB_VERSION_NUMBER=6,9,12,49
 
-PACKAGE_RELEASE_DATE=2022-05-10
+PACKAGE_RELEASE_DATE=2022-05-11
 
 
 # Ensure that make can run correctly
@@ -8520,120 +8518,6 @@ with_gnu_ld=$lt_cv_prog_gnu_ld
 
 
 
-# Check whether --with-gnu-ld was given.
-if test ${with_gnu_ld+y}
-then :
-  withval=$with_gnu_ld; test no = "$withval" || with_gnu_ld=yes
-else $as_nop
-  with_gnu_ld=no
-fi
-
-ac_prog=ld
-if test yes = "$GCC"; then
-  # Check if gcc -print-prog-name=ld gives a path.
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for ld used by $CC" >&5
-printf %s "checking for ld used by $CC... " >&6; }
-  case $host in
-  *-*-mingw*)
-    # gcc leaves a trailing carriage return, which upsets mingw
-    ac_prog=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
-  *)
-    ac_prog=`($CC -print-prog-name=ld) 2>&5` ;;
-  esac
-  case $ac_prog in
-    # Accept absolute paths.
-    [\\/]* | ?:[\\/]*)
-      re_direlt='/[^/][^/]*/\.\./'
-      # Canonicalize the pathname of ld
-      ac_prog=`$ECHO "$ac_prog"| $SED 's%\\\\%/%g'`
-      while $ECHO "$ac_prog" | $GREP "$re_direlt" > /dev/null 2>&1; do
-	ac_prog=`$ECHO $ac_prog| $SED "s%$re_direlt%/%"`
-      done
-      test -z "$LD" && LD=$ac_prog
-      ;;
-  "")
-    # If it fails, then pretend we aren't using GCC.
-    ac_prog=ld
-    ;;
-  *)
-    # If it is relative, then search for the first ld in PATH.
-    with_gnu_ld=unknown
-    ;;
-  esac
-elif test yes = "$with_gnu_ld"; then
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for GNU ld" >&5
-printf %s "checking for GNU ld... " >&6; }
-else
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for non-GNU ld" >&5
-printf %s "checking for non-GNU ld... " >&6; }
-fi
-if test ${lt_cv_path_LD+y}
-then :
-  printf %s "(cached) " >&6
-else $as_nop
-  if test -z "$LD"; then
-  lt_save_ifs=$IFS; IFS=$PATH_SEPARATOR
-  for ac_dir in $PATH; do
-    IFS=$lt_save_ifs
-    test -z "$ac_dir" && ac_dir=.
-    if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
-      lt_cv_path_LD=$ac_dir/$ac_prog
-      # Check to see if the program is GNU ld.  I'd rather use --version,
-      # but apparently some variants of GNU ld only accept -v.
-      # Break only if it was the GNU/non-GNU ld that we prefer.
-      case `"$lt_cv_path_LD" -v 2>&1 </dev/null` in
-      *GNU* | *'with BFD'*)
-	test no != "$with_gnu_ld" && break
-	;;
-      *)
-	test yes != "$with_gnu_ld" && break
-	;;
-      esac
-    fi
-  done
-  IFS=$lt_save_ifs
-else
-  lt_cv_path_LD=$LD # Let the user override the test with a path.
-fi
-fi
-
-LD=$lt_cv_path_LD
-if test -n "$LD"; then
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $LD" >&5
-printf "%s\n" "$LD" >&6; }
-else
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
-printf "%s\n" "no" >&6; }
-fi
-test -z "$LD" && as_fn_error $? "no acceptable ld found in \$PATH" "$LINENO" 5
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if the linker ($LD) is GNU ld" >&5
-printf %s "checking if the linker ($LD) is GNU ld... " >&6; }
-if test ${lt_cv_prog_gnu_ld+y}
-then :
-  printf %s "(cached) " >&6
-else $as_nop
-  # I'd rather use --version here, but apparently some GNU lds only accept -v.
-case `$LD -v 2>&1 </dev/null` in
-*GNU* | *'with BFD'*)
-  lt_cv_prog_gnu_ld=yes
-  ;;
-*)
-  lt_cv_prog_gnu_ld=no
-  ;;
-esac
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $lt_cv_prog_gnu_ld" >&5
-printf "%s\n" "$lt_cv_prog_gnu_ld" >&6; }
-with_gnu_ld=$lt_cv_prog_gnu_ld
-
-
-
-
-
-
-
-
-
     { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C compiler vendor" >&5
 printf %s "checking for C compiler vendor... " >&6; }
 if test ${ax_cv_c_compiler_vendor+y}
@@ -10003,6 +9887,10 @@ if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
         if test "x$PTHREAD_CC" != "x"
 then :
   CC="$PTHREAD_CC"
+fi
+        if test "x$PTHREAD_CXX" != "x"
+then :
+  CXX="$PTHREAD_CXX"
 fi
         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
         LIBS="$PTHREAD_LIBS $LIBS"
@@ -10408,7 +10296,7 @@ else $as_nop
              # step
              ax_pthread_save_ac_link="$ac_link"
              ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
-             ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+             ax_pthread_link_step=`printf "%s\n" "$ac_link" | sed "$ax_pthread_sed"`
              ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
              ax_pthread_save_CFLAGS="$CFLAGS"
              for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
@@ -10585,12 +10473,22 @@ fi
     #handle absolute path differently from PATH based program lookup
                      case "x$CC" in #(
   x/*) :
-    if as_fn_executable_p ${CC}_r
+
+			   if as_fn_executable_p ${CC}_r
 then :
   PTHREAD_CC="${CC}_r"
-fi ;; #(
+fi
+			   if test "x${CXX}" != "x"
+then :
+  if as_fn_executable_p ${CXX}_r
+then :
+  PTHREAD_CXX="${CXX}_r"
+fi
+fi
+			  ;; #(
   *) :
-    for ac_prog in ${CC}_r
+
+			   for ac_prog in ${CC}_r
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -10637,8 +10535,62 @@ fi
   test -n "$PTHREAD_CC" && break
 done
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
- ;;
-esac ;; #(
+
+			   if test "x${CXX}" != "x"
+then :
+  for ac_prog in ${CXX}_r
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_PTHREAD_CXX+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$PTHREAD_CXX"; then
+  ac_cv_prog_PTHREAD_CXX="$PTHREAD_CXX" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_PTHREAD_CXX="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+PTHREAD_CXX=$ac_cv_prog_PTHREAD_CXX
+if test -n "$PTHREAD_CXX"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $PTHREAD_CXX" >&5
+printf "%s\n" "$PTHREAD_CXX" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$PTHREAD_CXX" && break
+done
+test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX"
+
+fi
+
+                      ;;
+esac
+                     ;; #(
   *) :
      ;;
 esac
@@ -10648,6 +10600,8 @@ esac
 fi
 
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
+test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX"
+
 
 
 
@@ -11339,52 +11293,23 @@ fi
 # Check for sendfile support
 #
 ########
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking Linux compatible sendfile()" >&5
-printf %s "checking Linux compatible sendfile()... " >&6; }
-if test ${ac_cv_have_linux_sendfile+y}
-then :
-  printf %s "(cached) " >&6
-else $as_nop
-
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-    #undef _FILE_OFFSET_BITS
-    #include <sys/types.h>
-    #include <sys/socket.h>
-    #include <sys/sendfile.h>
-
-int
-main (void)
-{
-
-    sendfile(0, 0, (void *) 0, 0);
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"
-then :
-
-    ac_cv_have_linux_sendfile=yes
-
-else $as_nop
-
-    ac_cv_have_linux_sendfile=no
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.beam \
-    conftest$ac_exeext conftest.$ac_ext
-
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_have_linux_sendfile" >&5
-printf "%s\n" "$ac_cv_have_linux_sendfile" >&6; }
-if test $ac_cv_have_linux_sendfile = yes; then
-
-printf "%s\n" "#define HAVE_LINUX_SENDFILE 1" >>confdefs.h
-
-fi
+#AC_CACHE_CHECK([Linux compatible sendfile()],ac_cv_have_linux_sendfile,[
+#  AC_LINK_IFELSE([
+#    #undef _FILE_OFFSET_BITS
+#    #include <sys/types.h>
+#    #include <sys/socket.h>
+#    #include <sys/sendfile.h>
+#  ], [
+#    sendfile(0, 0, (void *) 0, 0);
+#  ], [
+#    ac_cv_have_linux_sendfile=yes
+#  ], [
+#    ac_cv_have_linux_sendfile=no
+#  ])
+#])
+#if test $ac_cv_have_linux_sendfile = yes; then
+#  AC_DEFINE([HAVE_LINUX_SENDFILE],[1], [Define if you have Linux-compatible sendfile()])
+#fi
 
 #
 # Set SETJMP_IS_THREAD_SAFE define.
@@ -23563,91 +23488,6 @@ fi
 
 
 # Check standard headers
-# Autoupdate added the next two lines to ensure that your configure
-# script's behavior did not change.  They are probably safe to remove.
-
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for egrep" >&5
-printf %s "checking for egrep... " >&6; }
-if test ${ac_cv_path_EGREP+y}
-then :
-  printf %s "(cached) " >&6
-else $as_nop
-  if echo a | $GREP -E '(a|b)' >/dev/null 2>&1
-   then ac_cv_path_EGREP="$GREP -E"
-   else
-     if test -z "$EGREP"; then
-  ac_path_EGREP_found=false
-  # Loop through the user's path and test for each of PROGNAME-LIST
-  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
-do
-  IFS=$as_save_IFS
-  case $as_dir in #(((
-    '') as_dir=./ ;;
-    */) ;;
-    *) as_dir=$as_dir/ ;;
-  esac
-    for ac_prog in egrep
-   do
-    for ac_exec_ext in '' $ac_executable_extensions; do
-      ac_path_EGREP="$as_dir$ac_prog$ac_exec_ext"
-      as_fn_executable_p "$ac_path_EGREP" || continue
-# Check for GNU ac_path_EGREP and select it if it is found.
-  # Check for GNU $ac_path_EGREP
-case `"$ac_path_EGREP" --version 2>&1` in
-*GNU*)
-  ac_cv_path_EGREP="$ac_path_EGREP" ac_path_EGREP_found=:;;
-*)
-  ac_count=0
-  printf %s 0123456789 >"conftest.in"
-  while :
-  do
-    cat "conftest.in" "conftest.in" >"conftest.tmp"
-    mv "conftest.tmp" "conftest.in"
-    cp "conftest.in" "conftest.nl"
-    printf "%s\n" 'EGREP' >> "conftest.nl"
-    "$ac_path_EGREP" 'EGREP$' < "conftest.nl" >"conftest.out" 2>/dev/null || break
-    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
-    as_fn_arith $ac_count + 1 && ac_count=$as_val
-    if test $ac_count -gt ${ac_path_EGREP_max-0}; then
-      # Best one so far, save it but keep looking for a better one
-      ac_cv_path_EGREP="$ac_path_EGREP"
-      ac_path_EGREP_max=$ac_count
-    fi
-    # 10*(2^10) chars as input seems more than enough
-    test $ac_count -gt 10 && break
-  done
-  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
-esac
-
-      $ac_path_EGREP_found && break 3
-    done
-  done
-  done
-IFS=$as_save_IFS
-  if test -z "$ac_cv_path_EGREP"; then
-    as_fn_error $? "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
-  fi
-else
-  ac_cv_path_EGREP=$EGREP
-fi
-
-   fi
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_EGREP" >&5
-printf "%s\n" "$ac_cv_path_EGREP" >&6; }
- EGREP="$ac_cv_path_EGREP"
-
-
-
-if ! test x"$ac_cv_header_stdc" = x"yes"; then
-    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: configure has detected that you do not have the ANSI standard C
-    header files.  Compilation cannot proceed.  Please install the ANSI C
-    headers and rerun this script." >&5
-printf "%s\n" "$as_me: WARNING: configure has detected that you do not have the ANSI standard C
-    header files.  Compilation cannot proceed.  Please install the ANSI C
-    headers and rerun this script." >&2;};
-fi
 
   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to enable assertions" >&5
 printf %s "checking whether to enable assertions... " >&6; }
@@ -24294,16 +24134,6 @@ printf "%s\n" "#define STAT_MACROS_BROKEN 1" >>confdefs.h
 
 fi
 
-
-
-# Obsolete code to be removed.
-if test $ac_cv_header_sys_time_h = yes; then
-
-printf "%s\n" "#define TIME_WITH_SYS_TIME 1" >>confdefs.h
-
-fi
-# End of obsolete code.
-
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether struct tm is in sys/time.h or time.h" >&5
 printf %s "checking whether struct tm is in sys/time.h or time.h... " >&6; }
 if test ${ac_cv_struct_tm+y}
@@ -25705,56 +25535,10 @@ printf "%s\n" "#define SIZEOF_VOID_P $ac_cv_sizeof_void_p" >>confdefs.h
 
 
 
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether our compiler supports __func__" >&5
-printf %s "checking whether our compiler supports __func__... " >&6; }
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-int
-main (void)
-{
-{ const char *func = __func__; return(func != 0 ? 0 : 1); }
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"
-then :
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-printf "%s\n" "yes" >&6; }
-else $as_nop
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
-printf "%s\n" "no" >&6; }
- { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether our compiler supports __FUNCTION__" >&5
-printf %s "checking whether our compiler supports __FUNCTION__... " >&6; }
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-int
-main (void)
-{
-{ const char *func = __FUNCTION__; return(func != 0 ? 0 : 1); }
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"
-then :
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-printf "%s\n" "yes" >&6; }
-
-printf "%s\n" "#define __func__ __FUNCTION__" >>confdefs.h
-
-else $as_nop
-  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
-printf "%s\n" "no" >&6; }
-
-printf "%s\n" "#define __func__ __FILE__" >>confdefs.h
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+#
+# Check for sendfile support
+#
+########
 
 ########
 #
@@ -26457,14 +26241,6 @@ printf "%s\n" "#define SELECT_TYPE_ARG5 ($3)" >>confdefs.h
 
 rm -rf conftest*
 
-if test ${ac_cv_func_setvbuf_reversed+y}
-then :
-  printf %s "(cached) " >&6
-else $as_nop
-  ac_cv_func_setvbuf_reversed=no
-fi
-
-
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for working strtod" >&5
 printf %s "checking for working strtod... " >&6; }
 if test ${ac_cv_func_strtod+y}
@@ -27658,60 +27434,6 @@ printf "%s\n" "#define HAVE_NAMESPACE_STD /**/" >>confdefs.h
 
   fi
 
-    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports ISO C++ standard library" >&5
-printf %s "checking whether the compiler supports ISO C++ standard library... " >&6; }
-if test ${ac_cv_cxx_have_std_libs+y}
-then :
-  printf %s "(cached) " >&6
-else $as_nop
-
-
- ac_ext=cpp
-ac_cpp='$CXXCPP $CPPFLAGS'
-ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
-
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <iostream>
-#include <map>
-#include <iomanip>
-#include <cmath>
-#ifdef HAVE_NAMESPACES
-using namespace std;
-#endif
-int
-main (void)
-{
-return 0;
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_cxx_try_compile "$LINENO"
-then :
-  ac_cv_cxx_have_std_libs=yes
-else $as_nop
-  ac_cv_cxx_have_std_libs=no
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
- ac_ext=cpp
-ac_cpp='$CXXCPP $CPPFLAGS'
-ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
-
-
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_cxx_have_std_libs" >&5
-printf "%s\n" "$ac_cv_cxx_have_std_libs" >&6; }
-if test "$ac_cv_cxx_have_std_libs" = yes; then
-
-printf "%s\n" "#define HAVE_STD_LIBS /**/" >>confdefs.h
-
-fi
-
     # Check whether --enable-openmp was given.
 if test ${enable_openmp+y}
 then :
diff --git a/configure.ac b/configure.ac
index 67958afce1..7143ad113e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,7 +19,7 @@
 #  notice and this notice are preserved.
 
 # Process this file with autoconf to create configure script.
-AC_PREREQ(2.69)
+AC_PREREQ([2.71])
 
 # ==============================================================================
 # Initalize Automake
@@ -42,11 +42,7 @@ m4_define([magick_release_date],
             printf %s "$d"
           ]))
 
-AC_INIT([magick_name],
-        [magick_version],
-        [magick_bugreport],
-        [magick_tarname],
-        [magick_url])
+AC_INIT([magick_name],[magick_version],[magick_bugreport],[magick_tarname],[magick_url])
 
 AC_CONFIG_SRCDIR([magick/MagickCore.h])
 AC_CONFIG_AUX_DIR([config])
@@ -54,7 +50,6 @@ AC_REQUIRE_AUX_FILE([tap-driver.sh])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_HEADERS([config/config.h])
 AX_PREFIX_CONFIG_H([magick/magick-baseconfig.h],[MagickCore])
-AC_CANONICAL_SYSTEM
 AC_CANONICAL_TARGET
 
 AM_INIT_AUTOMAKE([foreign no-define color-tests parallel-tests -Wall -Wno-portability subdir-objects dist-bzip2 dist-lzip dist-xz dist-zip tar-ustar])
@@ -276,10 +271,8 @@ AC_USE_SYSTEM_EXTENSIONS
 m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
 AC_PROG_CC
 AC_PROG_CPP
-AC_PROG_LD
 LT_PATH_LD
 AC_SUBST([LD])
-AC_PROG_CC_C99
 AM_PROG_CC_C_O
 AX_CFLAGS_WARN_ALL
 AC_PROG_INSTALL
@@ -533,23 +526,23 @@ AC_SUBST([LFS_CPPFLAGS])
 # Check for sendfile support
 #
 ########
-AC_CACHE_CHECK([Linux compatible sendfile()],ac_cv_have_linux_sendfile,[
-  AC_TRY_LINK([
-    #undef _FILE_OFFSET_BITS
-    #include <sys/types.h>
-    #include <sys/socket.h>
-    #include <sys/sendfile.h>
-  ], [
-    sendfile(0, 0, (void *) 0, 0);
-  ], [
-    ac_cv_have_linux_sendfile=yes
-  ], [
-    ac_cv_have_linux_sendfile=no
-  ])
-])
-if test $ac_cv_have_linux_sendfile = yes; then
-  AC_DEFINE([HAVE_LINUX_SENDFILE],[1], [Define if you have Linux-compatible sendfile()])
-fi
+#AC_CACHE_CHECK([Linux compatible sendfile()],ac_cv_have_linux_sendfile,[
+#  AC_LINK_IFELSE([
+#    #undef _FILE_OFFSET_BITS
+#    #include <sys/types.h>
+#    #include <sys/socket.h>
+#    #include <sys/sendfile.h>
+#  ], [
+#    sendfile(0, 0, (void *) 0, 0);
+#  ], [
+#    ac_cv_have_linux_sendfile=yes
+#  ], [
+#    ac_cv_have_linux_sendfile=no
+#  ])
+#])
+#if test $ac_cv_have_linux_sendfile = yes; then
+#  AC_DEFINE([HAVE_LINUX_SENDFILE],[1], [Define if you have Linux-compatible sendfile()])
+#fi
 
 #
 # Set SETJMP_IS_THREAD_SAFE define.
@@ -931,12 +924,6 @@ AC_SUBST([MODULE_EXTRA_CPPFLAGS])
 AC_SUBST([LIBRARY_EXTRA_CPPFLAGS])
 
 # Check standard headers
-AC_HEADER_STDC
-if ! test x"$ac_cv_header_stdc" = x"yes"; then
-    AC_MSG_WARN([configure has detected that you do not have the ANSI standard C
-    header files.  Compilation cannot proceed.  Please install the ANSI C
-    headers and rerun this script.]);
-fi
 AC_HEADER_ASSERT
 AC_HEADER_DIRENT
 
@@ -953,7 +940,6 @@ AC_HEADER_STDBOOL
 AC_C_VOLATILE
 AC_C_STRINGIZE
 AC_HEADER_STAT
-AC_HEADER_TIME
 AC_STRUCT_TM
 AC_STRUCT_TIMEZONE
 AC_SYS_INTERPRETER
@@ -1008,20 +994,10 @@ AC_CHECK_SIZEOF([unsigned long long])
 
 AC_CHECK_SIZEOF([void *])
 
-AC_MSG_CHECKING([whether our compiler supports __func__])
-AC_TRY_COMPILE([],
- [{ const char *func = __func__; return(func != 0 ? 0 : 1); }],
- AC_MSG_RESULT([yes]),
- AC_MSG_RESULT([no])
- AC_MSG_CHECKING([whether our compiler supports __FUNCTION__])
- AC_TRY_COMPILE([],
-   [{ const char *func = __FUNCTION__; return(func != 0 ? 0 : 1); }],
-   AC_MSG_RESULT([yes])
-   AC_DEFINE(__func__, __FUNCTION__,
-     [Define to appropriate substitute if compiler does not have __func__]),
-   AC_MSG_RESULT([no])
-   AC_DEFINE(__func__, __FILE__,
-     [Define to appropriate substitute if compiler does not have __func__])))
+#
+# Check for sendfile support
+#
+########
 
 ########
 #
@@ -1035,7 +1011,6 @@ AC_FUNC_MALLOC
 AC_FUNC_MEMCMP
 AC_FUNC_REALLOC
 AC_FUNC_SELECT_ARGTYPES
-AC_FUNC_SETVBUF_REVERSED
 AC_FUNC_STRTOD
 AC_FUNC_STRERROR_R
 AC_FUNC_VPRINTF
@@ -1117,7 +1092,6 @@ if test "$with_magick_plus_plus" = 'yes'; then
     AX_CXX_BOOL
     AX_CXX_NAMESPACES
     AX_CXX_NAMESPACE_STD
-    AC_CXX_HAVE_STD_LIBS
     AC_OPENMP([C++])
     AC_LANG_POP
 
diff --git a/m4/ax_pthread.m4 b/m4/ax_pthread.m4
index 1598d077ff..9f35d13914 100644
--- a/m4/ax_pthread.m4
+++ b/m4/ax_pthread.m4
@@ -14,20 +14,24 @@
 #   flags that are needed. (The user can also force certain compiler
 #   flags/libs to be tested by setting these environment variables.)
 #
-#   Also sets PTHREAD_CC to any special C compiler that is needed for
-#   multi-threaded programs (defaults to the value of CC otherwise). (This
-#   is necessary on AIX to use the special cc_r compiler alias.)
+#   Also sets PTHREAD_CC and PTHREAD_CXX to any special C compiler that is
+#   needed for multi-threaded programs (defaults to the value of CC
+#   respectively CXX otherwise). (This is necessary on e.g. AIX to use the
+#   special cc_r/CC_r compiler alias.)
 #
 #   NOTE: You are assumed to not only compile your program with these flags,
 #   but also to link with them as well. For example, you might link with
 #   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
+#   $PTHREAD_CXX $CXXFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
 #
 #   If you are only building threaded programs, you may wish to use these
 #   variables in your default LIBS, CFLAGS, and CC:
 #
 #     LIBS="$PTHREAD_LIBS $LIBS"
 #     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+#     CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS"
 #     CC="$PTHREAD_CC"
+#     CXX="$PTHREAD_CXX"
 #
 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
 #   has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to
@@ -83,7 +87,7 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 27
+#serial 31
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [
@@ -105,6 +109,7 @@ if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
         ax_pthread_save_CFLAGS="$CFLAGS"
         ax_pthread_save_LIBS="$LIBS"
         AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
+        AS_IF([test "x$PTHREAD_CXX" != "x"], [CXX="$PTHREAD_CXX"])
         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
         LIBS="$PTHREAD_LIBS $LIBS"
         AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
@@ -386,7 +391,7 @@ if test "x$ax_pthread_clang" = "xyes"; then
              # step
              ax_pthread_save_ac_link="$ac_link"
              ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
-             ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+             ax_pthread_link_step=`AS_ECHO(["$ac_link"]) | sed "$ax_pthread_sed"`
              ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
              ax_pthread_save_CFLAGS="$CFLAGS"
              for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
@@ -482,18 +487,28 @@ if test "x$ax_pthread_ok" = "xyes"; then
                     [#handle absolute path differently from PATH based program lookup
                      AS_CASE(["x$CC"],
                          [x/*],
-                         [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
-                         [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+                         [
+			   AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])
+			   AS_IF([test "x${CXX}" != "x"], [AS_IF([AS_EXECUTABLE_P([${CXX}_r])],[PTHREAD_CXX="${CXX}_r"])])
+			 ],
+                         [
+			   AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])
+			   AS_IF([test "x${CXX}" != "x"], [AC_CHECK_PROGS([PTHREAD_CXX],[${CXX}_r],[$CXX])])
+			 ]
+                     )
+                    ])
                 ;;
             esac
         fi
 fi
 
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
+test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX"
 
 AC_SUBST([PTHREAD_LIBS])
 AC_SUBST([PTHREAD_CFLAGS])
 AC_SUBST([PTHREAD_CC])
+AC_SUBST([PTHREAD_CXX])
 
 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
 if test "x$ax_pthread_ok" = "xyes"; then