Stop using -ansi -fno-gnu-keywords in Linux

There is no need for -fno-gnu-keywords (which was implied by -ansi) in the
current code.
-ansi disables GCC built-in functions, which add optimizations and extra
security checks in some cases. It may be good to use it (and -pedantic) while
developing to try to keep the code ANSI standard, but users should have binaries
compiled without the option.
Add NO_STATIC option to Linux Makefile