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.
Teach the Makefile and Ninja generators to substitute for an <INCLUDES>
placeholder instead of putting -I in <FLAGS>. Update our values for
CMAKE_<LANG>_COMPILE_OBJECT,
CMAKE_<LANG>_CREATE_ASSEMBLY_SOURCE, and
CMAKE_<LANG>_CREATE_PREPROCESSED_SOURCE
to place <INCLUDES> just before <FLAGS>.
Previously we linked C, Fortran, and ASM shared libraries compiled with
the HP compiler using a direct invocation of the linker (ld). This
behavior was left historically from support for an ancient HP C compiler
that did not know how to create shared libraries. Fortran shared
libraries need to be linked with the compiler to get the language
runtime library dependencies as is already done for C++.
Update the HP-UX-HP* platform information to use the compiler front end
when linking shared libraries. This works on modern HP tools and
produces correct behavior. If there is a need to support older tools
again we can add a special case for them.
Move HP flags out of Platform/HP-UX.cmake into platform-specific
compiler information files "Platform/HP-UX-HP-<lang>.cmake". Factor
common values into "Platform/HP-UX-HP.cmake" and load it from the
per-language files.
Brad King