Teach CMakePlatformId.h to construct an "INFO:compiler_version[]" string
literal from macros COMPILER_VERSION_(MAJOR|MINOR|PATCH|TWEAK) to be
defined in CMake(C|CXX)CompilerId.(c|cpp) for each compiler. Provide
conversion macros DEC() and HEX() to decode decimal or hex digits from
integer values. Parse the version out of the compiler id binary along
with the other INFO values already present.
Store the result in variable CMAKE_<LANG>_COMPILER_VERSION in the format
"major[.minor[.patch[.tweak]]]". Save the value persistently in
CMake(C|CXX)Compiler.cmake in the build tree. Document the variable for
internal use since we do not set it everywhere yet.
Report the compiler version on the compiler id result line e.g.
The C compiler identification is GNU 4.5.2
Report CMAKE_(C|CXX)_COMPILER_(ID|VERSION) in SystemInformation test.
This teaches CMake to detect implicit link information for C, C++, and
Fortran compilers. We detect the implicit linker search directories and
implicit linker options for UNIX-like environments using verbose output
from compiler front-ends. We store results in new variables called
CMAKE_<LANG>_IMPLICIT_LINK_LIBRARIES
CMAKE_<LANG>_IMPLICIT_LINK_DIRECTORIES
The implicit libraries can contain linker flags as well as library
names.