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 "link" option to Linux Makefile
Add DESTDIR option to Linux Makefile
Fix typo
Use Linux-style EOL for non Windows specific files
Update licensing information

Substitute LICENSE.LGPL for the latest copy from http://www.gnu.org/. And update
the FSF address and links in all the file headers.