Blosc
CFLAGS from environment are not respected
Describe the bug
Normally, CMake defaults the C compiler flags to the value of CFLAGS environment variable. However, c-blosc2 overrides CMAKE_C_FLAGS and prevents CMake from respecting that.
To Reproduce
CFLAGS="-frecord-gcc-switches" cmake .. -G Ninja
ninja -v |& grep record-gcc-switches
Expected behavior
-frecord-gcc-switches should be found on the compiler command-line.
Logs n/a
System information:
- OS: Gentoo Linux amd64
- Compiler: gcc 12.2.1
- Version: v2.6.1
Additional context I suppose adding something like this on top would work. However, I'm not sure if there isn't a cleaner solution:
if(NOT CMAKE_C_FLAGS)
set(CMAKE_C_FLAGS "$ENV{CFLAGS}")
endif()
Indeed CGLAGS seems to be the traditional standard approach to modify C options locally outside the build chain, but also inside the build chain. For example, in configure.ac you would write:
CFLAGS="$CFLAGS -std=c11"
Therefore, I wonder whether CMake should manipulate CFLAGS instead of directly modifying CMAKE_C_FLAGS:
CMake uses this environment variable value, in combination with its own builtin default flags for the toolchain, to initialize and store the
CMAKE_C_FLAGScache entry. [...] For any configuration run (including the first), the environment variable will be ignored if theCMAKE_C_FLAGSvariable is already defined.
However, that approach might require some extra changes, for example here:
# Set the "-msse2" build flag only if the CMAKE_C_FLAGS is not already set.
# Probably "-msse2" should be appended to CMAKE_C_FLAGS_RELEASE.
if(CMAKE_C_COMPILER_ID STREQUAL GNU OR CMAKE_C_COMPILER_ID STREQUAL Clang OR CMAKE_C_COMPILER_ID STREQUAL Intel)
if(NOT CMAKE_C_FLAGS AND COMPILER_SUPPORT_SSE2)
set(CMAKE_C_FLAGS -msse2 CACHE STRING "C flags." FORCE)
endif()
endif()
