The Sun compiler does not provide the proper vector constructor to
initialize it from an iterator pair of a non-matching type. Extend the
ParseUnixCommandLine API to provide a vector of the proper type so no
conversion is needed.
Many compilers we support do not provide the at() member of std::map.
Use the workaround added by commit a7e7a04a (Fix run_compile_commands
build on Apple GCC 3.3, 2011-05-16) for all compilers.
Xcode 2.x forgets to create the target output directory before linking
the individual architecture pieces of a universal binary for the target
CMakeLibTests. Then it passes the directory to -L and -F options when
linking the and warns that the directory does not exist. We work around
the problem by using a pre-build rule on the target to create the output
directory.