mmap-wx: split compilation flags

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
mmap-wx: slight style improvements

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
mmap-wx: dump /proc/self/maps when successful

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
mmap-wx: no longer fail on vanilla kernel

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
mmap-wx: update program output in README

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>