Document these variables.
Change our convention for setting these variables from:
set(CMAKE_C_FLAGS_INIT "...")
to
string(APPEND CMAKE_C_FLAGS_INIT " ...")
so that any value previously set by a toolchain file will be used.
Automate the conversion with:
sed -i 's/set *(\(CMAKE_\(C\|CXX\|Fortran\|RC\|ASM\|${[^}]\+}\)_FLAGS\(_[^_]\+\)\?_INIT \+"\)/string(APPEND \1 /' \
Modules/Compiler/*.cmake Modules/Platform/*.cmake
and follow up with some manual fixes (e.g. to cases that already
meant to append). Also revert the automated changes to contexts
that are not protected from running multiple times.
Refactor options out of `Modules/Compiler/Intel-{ASM,C,CXX,Fortran}.cmake`
into a common helper in `Modules/Compiler/Intel.cmake`. Condition
them to be used only on non-Windows hosts where the Intel compiler
is GNU-like instead of MSVC-like.
Previously this worked only because the options were later overridden
by `Modules/Platform/Windows-Intel*.cmake`, but it is cleaner to not
set the options in the first place.
The commit "Split Intel compiler information files" moved some Linux
specific flags into the platform-independent Intel compiler info files.
This moves them back.