Build fix for Clang compilers

[ercansormaz]

When I try to build xevd to use in ffmpeg on Intel MacOS Sequoia 15.7.9

cmake -DCMAKE_FIND_ROOT_PATH="$HOME/Applications/ffmpeg_library" -DCMAKE_INSTALL_PREFIX="$HOME/Applications/ffmpeg_library" -DCMAKE_BUILD_TYPE=Release ..
Version string has been taken from git tag.
XEVD VERSION=0.7.0
-- The C compiler identification is AppleClang 17.0.0.17000013
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
CMAKE_BUILD_TYPE=Release
SET_PROF=MAIN
SYSTEM_PROCESSOR=x86_64
ARM=
Using GNU GCC compiler
c Flags: -O3 -DNDEBUG -fomit-frame-pointer -pthread -std=c99 -Wall -Werror -Wno-pointer-sign -Wno-pointer-to-int-cast -Wno-maybe-uninitialized -Wno-unused-function -Wno-unused-but-set-variable -Wno-unused-variable -Wno-attributes -Wno-unknown-pragmas -Wno-stringop-overflow
linker Flags: -lm
-- Performing Test COMPILER_HAS_HIDDEN_VISIBILITY
-- Performing Test COMPILER_HAS_HIDDEN_VISIBILITY - Failed
-- Performing Test COMPILER_HAS_HIDDEN_INLINE_VISIBILITY
-- Performing Test COMPILER_HAS_HIDDEN_INLINE_VISIBILITY - Failed
-- Performing Test COMPILER_HAS_DEPRECATED_ATTR
-- Performing Test COMPILER_HAS_DEPRECATED_ATTR - Failed
-- Performing Test COMPILER_HAS_DEPRECATED
-- Performing Test COMPILER_HAS_DEPRECATED - Failed
-- Configuring done (1.4s)
-- Generating done (0.1s)
-- Build files have been written to: /Users/ercan/Applications/ffmpeg_sources/xevd/build

make
[ 1%] Building C object src_main/CMakeFiles/xevd.dir/xevdm.c.o
error: unknown warning option '-Wno-maybe-uninitialized'; did you mean '-Wno-uninitialized'? [-Werror,-Wunknown-warning-option]
error: unknown warning option '-Wno-stringop-overflow'; did you mean '-Wno-shift-overflow'? [-Werror,-Wunknown-warning-option]
make[2]: *** [src_main/CMakeFiles/xevd.dir/xevdm.c.o] Error 1
make[1]: *** [src_main/CMakeFiles/xevd.dir/all] Error 2
make: *** [all] Error 2

[kpchoi]

Thanks for the fix. However, I think the changes need another review before merging:

• CMAKE_CXX_COMPILER_ID is used for CMAKE_C_FLAGS; this should likely use CMAKE_C_COMPILER_ID.
• AppleClang is not covered by the Clang condition, although the reported issue occurs with AppleClang.
• -Wno-shift-overflow is not equivalent to the removed GCC-specific -Wno-stringop-overflow; please verify whether it is actually needed.
• Please verify the compiler-specific warning flags for GCC, Clang, and AppleClang separately.

The underlying issue is valid, but I don't think this patch is ready to merge as-is.