set(_GNU_COMMON_C_CXX_FLAGS "\
  -fexceptions \
  -fno-common \
  -fcolor-diagnostics \
  -faligned-allocation \
  -fdebug-default-version=4 \
  -ffunction-sections \
  -fdata-sections \
  -Wall \
  -Wextra \
  -Wno-parentheses \
  -Wno-implicit-const-int-float-conversion \
  -Wno-unknown-warning-option \
  -pipe \
  -D_THREAD_SAFE \
  -D_PTHREADS \
  -D_REENTRANT \
  -D_LARGEFILE_SOURCE \
  -D__STDC_CONSTANT_MACROS \
  -D__STDC_FORMAT_MACROS \
  -D__LONG_LONG_SUPPORTED \
")

if (CMAKE_SYSTEM_NAME MATCHES "^(Android|Linux)$")
  string(APPEND _GNU_COMMON_C_CXX_FLAGS " -D_GNU_SOURCE")
endif()

if (CMAKE_SYSTEM_NAME MATCHES "^(Darwin|Linux)$")
  string(APPEND _GNU_COMMON_C_CXX_FLAGS " -DLIBCXX_BUILDING_LIBCXXRT")
endif()

if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
  # Use .init_array instead of .ctors (default for old clang versions)
  # See: https://maskray.me/blog/2021-11-07-init-ctors-init-array
  string(APPEND _GNU_COMMON_C_CXX_FLAGS " -fuse-init-array")
endif()

if (ANDROID)
  include_directories(SYSTEM ${CMAKE_ANDROID_NDK}/sources/cxx-stl/llvm-libc++abi/include)

  # There is no usable _FILE_OFFSET_BITS=64 support in Androids until API 21. And it's incomplete until at least API 24.
  # https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md
else()
  string(APPEND _GNU_COMMON_C_CXX_FLAGS " -D_FILE_OFFSET_BITS=64")
endif()

if (CMAKE_SYSTEM_PROCESSOR MATCHES "^(arm.*|aarch64|ppc64le)")
  string(APPEND _GNU_COMMON_C_CXX_FLAGS " -fsigned-char")
endif()

include(global_flags.compiler.gnu.march)
string(APPEND _GNU_COMMON_C_CXX_FLAGS " ${_GNU_MARCH_C_CXX_FLAGS}")


set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${_GNU_COMMON_C_CXX_FLAGS}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_GNU_COMMON_C_CXX_FLAGS} \
  -Woverloaded-virtual \
  -Wimport-preprocessor-directive-pedantic \
  -Wno-undefined-var-template \
  -Wno-return-std-move \
  -Wno-defaulted-function-deleted \
  -Wno-pessimizing-move \
  -Wno-deprecated-anon-enum-enum-conversion \
  -Wno-deprecated-enum-enum-conversion \
  -Wno-deprecated-enum-float-conversion \
  -Wno-ambiguous-reversed-operator \
  -Wno-deprecated-volatile \
")