[compiler-rt] Move -fno-omit-frame-pointer check to common config-ix

[mgorny]

Summary

9ee64c374605683ae80b9641d5312a72c2a67336 has started using
COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG inside scudo. However,
the relevant CMake check was performed in builtin-config-ix.cmake,
so the definition was missing when builtins were not built. Move
the check to config-ix.cmake, so that it runs unconditionally of
the components being built.

Fixes PR#51847

[tstellar]

LGTM. Thank you.

compiler-rt/cmake/builtin-config-ix.cmake

 include(BuiltinTests)
 include(CheckCSourceCompiles)
 
 # Make all the tests only check the compiler
 set(TEST_COMPILE_ONLY On)
 
 # Check host compiler support for certain flags
 builtin_check_c_compiler_flag(-fPIC                 COMPILER_RT_HAS_FPIC_FLAG)
 builtin_check_c_compiler_flag(-fPIE                 COMPILER_RT_HAS_FPIE_FLAG)
 builtin_check_c_compiler_flag(-fno-builtin          COMPILER_RT_HAS_FNO_BUILTIN_FLAG)
 builtin_check_c_compiler_flag(-std=c11              COMPILER_RT_HAS_STD_C11_FLAG)
 builtin_check_c_compiler_flag(-fvisibility=hidden   COMPILER_RT_HAS_VISIBILITY_HIDDEN_FLAG)
-builtin_check_c_compiler_flag(-fomit-frame-pointer  COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG)
 builtin_check_c_compiler_flag(-ffreestanding        COMPILER_RT_HAS_FREESTANDING_FLAG)
 builtin_check_c_compiler_flag(-fxray-instrument     COMPILER_RT_HAS_XRAY_COMPILER_FLAG)
 
 builtin_check_c_compiler_source(COMPILER_RT_HAS_ATOMIC_KEYWORD
 "
 int foo(int x, int y) {
  _Atomic int result = x * y;
  return result;

compiler-rt/cmake/config-ix.cmake

set(MINGW_LIBRARIES mingw32 ${MINGW_RUNTIME} moldname mingwex msvcrt advapi32
                         shell32 user32 kernel32 mingw32 ${MINGW_RUNTIME}
                         moldname mingwex msvcrt)
     list(APPEND CMAKE_REQUIRED_LIBRARIES ${MINGW_LIBRARIES})
   endif()
 endif ()
 
 # CodeGen options.
 check_c_compiler_flag(-ffreestanding         COMPILER_RT_HAS_FFREESTANDING_FLAG)
+check_c_compiler_flag(-fomit-frame-pointer   COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG)
 check_c_compiler_flag(-std=c11               COMPILER_RT_HAS_STD_C11_FLAG)
 check_cxx_compiler_flag(-fPIC                COMPILER_RT_HAS_FPIC_FLAG)
 check_cxx_compiler_flag(-fPIE                COMPILER_RT_HAS_FPIE_FLAG)
 check_cxx_compiler_flag(-fno-builtin         COMPILER_RT_HAS_FNO_BUILTIN_FLAG)
 check_cxx_compiler_flag(-fno-exceptions      COMPILER_RT_HAS_FNO_EXCEPTIONS_FLAG)
 check_cxx_compiler_flag(-fomit-frame-pointer COMPILER_RT_HAS_FOMIT_FRAME_POINTER_FLAG)
 check_cxx_compiler_flag(-funwind-tables      COMPILER_RT_HAS_FUNWIND_TABLES_FLAG)
 check_cxx_compiler_flag(-fno-stack-protector COMPILER_RT_HAS_FNO_STACK_PROTECTOR_FLAG)