`CMAKE_C_FLAGS` is not set by curl, but may contain custom options
required for a successful compiler run, when invoked by these tests.
One such case is when configuring Visual Studio or clang-cl via compiler
options, instead of envs.
Cherry-picked from #18301
Closes #18307
if(APPLE AND CMAKE_OSX_SYSROOT)
string(APPEND CURL_CPP " -isysroot ${CMAKE_OSX_SYSROOT}")
endif()
+ string(APPEND CURL_CPP " ${CMAKE_C_FLAGS}")
# Add header directories, like autotools builds do.
get_property(_include_dirs TARGET ${LIB_SELECTED} PROPERTY INCLUDE_DIRECTORIES)
foreach(_include_dir IN LISTS _include_dirs)