depends: add zeromq no librt patch

depends/packages/zeromq.mk

@@ -8,6 +8,7 @@ $(package)_patches += macos_mktemp_check.patch
 $(package)_patches += builtin_sha1.patch
 $(package)_patches += fix_have_windows.patch
 $(package)_patches += cmake_minimum.patch
+$(package)_patches += no_librt.patch
 
 define $(package)_set_vars
   $(package)_config_opts = --without-docs --disable-shared --disable-valgrind
@@ -22,7 +23,8 @@ define $(package)_preprocess_cmds
   patch -p1 < $($(package)_patch_dir)/macos_mktemp_check.patch && \
   patch -p1 < $($(package)_patch_dir)/builtin_sha1.patch && \
   patch -p1 < $($(package)_patch_dir)/fix_have_windows.patch && \
-  patch -p1 < $($(package)_patch_dir)/cmake_minimum.patch
+  patch -p1 < $($(package)_patch_dir)/cmake_minimum.patch && \
+  patch -p1 < $($(package)_patch_dir)/no_librt.patch
 endef
 
 define $(package)_config_cmds

depends/patches/zeromq/no_librt.patch

@@ -0,0 +1,54 @@
+We don't use librt, so don't try and link against it.
+
+Related to: https://github.com/zeromq/libzmq/pull/4702.
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 03462271..87ceab3c 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -564,13 +564,6 @@ else()
+   check_cxx_symbol_exists(SO_BUSY_POLL sys/socket.h ZMQ_HAVE_BUSY_POLL)
+ endif()
+
+-if(NOT MINGW)
+-  find_library(RT_LIBRARY rt)
+-  if(RT_LIBRARY)
+-    set(pkg_config_libs_private "${pkg_config_libs_private} -lrt")
+-  endif()
+-endif()
+-
+ find_package(Threads)
+
+ if(WIN32 AND NOT CYGWIN)
+@@ -588,9 +581,7 @@ if(WIN32 AND NOT CYGWIN)
+ endif()
+
+ if(NOT MSVC)
+-  set(CMAKE_REQUIRED_LIBRARIES rt)
+   check_cxx_symbol_exists(clock_gettime time.h HAVE_CLOCK_GETTIME)
+-  set(CMAKE_REQUIRED_LIBRARIES)
+
+   check_cxx_symbol_exists(fork unistd.h HAVE_FORK)
+   check_cxx_symbol_exists(gethrtime sys/time.h HAVE_GETHRTIME)
+@@ -1503,10 +1494,6 @@ if(BUILD_SHARED)
+     target_link_libraries(libzmq iphlpapi)
+   endif()
+
+-  if(RT_LIBRARY)
+-    target_link_libraries(libzmq -lrt)
+-  endif()
+-
+   if(norm_FOUND)
+       target_link_libraries(libzmq norm::norm)
+   endif()
+@@ -1553,10 +1540,6 @@ if(BUILD_STATIC)
+     target_link_libraries(libzmq-static iphlpapi)
+   endif()
+
+-  if(RT_LIBRARY)
+-    target_link_libraries(libzmq-static -lrt)
+-  endif()
+-
+   if(CMAKE_SYSTEM_NAME MATCHES "QNX")
+     add_definitions(-DUNITY_EXCLUDE_MATH_H)
+   endif()