Do feature test before adding -Bsymbolic-functions, cmake part (#889)

CMakeLists.txt

@@ -537,7 +537,11 @@ target_link_libraries(harfbuzz-subset harfbuzz ${THIRD_PARTY_LIBS})
 
 if (UNIX OR MINGW)
   # Make symbols link locally
-  link_libraries(-Bsymbolic-functions)
+  include(CheckCXXCompilerFlag)
+  check_cxx_compiler_flag(-Bsymbolic-functions CXX_SUPPORTS_FLAG_BSYMB_FUNCS)
+  if(CXX_SUPPORTS_FLAG_BSYMB_FUNCS)
+    link_libraries(-Bsymbolic-functions)
+  endif()  
 
   if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     # Make sure we don't link to libstdc++