Testing - Add a new compilation on Clang without PCH #540

Fixed PCH issue for mac os

Author: dpasukhi

adm/cmake/occt_defs_flags.cmake

@@ -151,15 +151,27 @@ elseif (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPIL
     # /GL (whole program optimization) is similar to -flto (Link Time Optimization) in GCC/Clang.
     # /GF (eliminate duplicate strings) doesn't have a direct equivalent in GCC/Clang, but the compilers do string pooling automatically.
     # /Gy (enable function-level linking) is similar to -ffunction-sections in GCC/Clang.
-    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -fomit-frame-pointer -flto -ffunction-sections")
-    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O3 -fomit-frame-pointer -flto -ffunction-sections")
+    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -fomit-frame-pointer")
+    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O3 -fomit-frame-pointer")
+    
+    # Apply LTO optimization on all platforms
+    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -flto")
+    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -flto")
+    
+    # Apply function sections only on non-macOS platforms
+    if (NOT APPLE)
+      set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -ffunction-sections")
+      set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -ffunction-sections")
+    endif()
 
-    # Link-Time Code Generation(LTCG) is requared for Whole Program Optimisation(GL)
+    # Link-Time Code Generation (LTCG) is required for Whole Program Optimization
     set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} -flto")
     set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} -flto")
     set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "${CMAKE_STATIC_LINKER_FLAGS_RELEASE} -flto")
     set(CMAKE_MODULE_LINKER_FLAGS_RELEASE "${CMAKE_MODULE_LINKER_FLAGS_RELEASE} -flto")
-    if (NOT WIN32)
+    
+    # Add garbage collection sections only on Linux (not on macOS or Windows)
+    if (NOT WIN32 AND NOT APPLE)
       set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} -Wl,--gc-sections")
       set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "${CMAKE_STATIC_LINKER_FLAGS_RELEASE} -Wl,--gc-sections")
       set(CMAKE_MODULE_LINKER_FLAGS_RELEASE "${CMAKE_MODULE_LINKER_FLAGS_RELEASE} -Wl,--gc-sections")