From ffbe6103494365060553c8edf3ed4a1db1738bc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zdenko=20Podobn=C3=BD?= <zdenop@gmail.com>
Date: Wed, 22 Jul 2015 14:40:07 +0200
Subject: [PATCH] add check for opencl requirements

---
 configure.ac | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)
 mode change 100644 => 100755 configure.ac

diff --git a/configure.ac b/configure.ac
old mode 100644
new mode 100755
index 8d11ba99e8..284451c13b
--- a/configure.ac
+++ b/configure.ac
@@ -160,12 +160,27 @@ AC_ARG_ENABLE([opencl],
     [enable_opencl=$enableval],
     [enable_opencl="no"])
 AC_MSG_RESULT($enable_opencl)
-AM_CONDITIONAL([USE_OPENCL], [test "$enable_opencl" = "yes"])
 if test "$enable_opencl" = "yes"; then
-  AC_SUBST([AM_CPPFLAGS], [-DUSE_OPENCL])
-  AC_SUBST([OPENCL_HDR_PATH],[$OPENCL_INC])
-  AC_SUBST([OPENCL_LIB],[$OPENCL_LIBS])
+    # check for opencl header
+    AC_CHECK_HEADERS(CL/cl.h, [], [
+        AC_CHECK_HEADERS(OpenCL/cl.h, [], [
+            AC_MSG_ERROR(OpenCL headers file was not found)
+            ])
+    ])
+    # check for libtiff
+    have_tiff=false
+    AC_CHECK_HEADERS(tiffio.h, have_tiff=true, have_tiff=false)
+    if !($have_tiff); then
+        AC_MSG_WARN(OpenCL will not be used - required TIFF headers not found)
+        AC_MSG_WARN(Try to install libtiff-dev?? package.)
+        enable_opencl="no"
+    else
+        AC_SUBST([AM_CPPFLAGS], [-DUSE_OPENCL])
+        AC_SUBST([OPENCL_HDR_PATH],[$OPENCL_INC])
+        AC_SUBST([OPENCL_LIB],[$OPENCL_LIBS])
+    fi
 fi
+AM_CONDITIONAL([USE_OPENCL], [test "$enable_opencl" = "yes"])
 
 # check whether to build tesseract with -fvisibility=hidden -fvisibility-inlines-hidden
 # http://gcc.gnu.org/wiki/Visibility