The GCC option `--posixly` was introduced to enable the compilation
of POSIX code in Jehanne, assuming that building native C code
would have been the default.
However since
- GCC is itself a POSIX program and most programmers that use it
assume a POSIX environment
- GCC is used as a cross compiler to build Jehanne from POSIX systems
- C++ will never be native in Jehanne (too much complexity for a
system that want to be simple) and thus will always require a
POSIX environment to build POSIX C++ code
I decided to invert the logic.
Thus now by default GCC, by default, will build POSIX programs,
loading required libraries and headers from /posix subdirectories.
The new option `-9` will remove such POSIX stuff when compiling
native C programs.
