master
Dynamically determine supported compiler flags during configure
Refine win32 api checks and usage.
add entries for msys
Update iconv.m4
Forgot to add file in r1257.
Copy lib-link.m4,lib-prefix.m4 and lib-ld.m4 from http://git.savannah.gnu.org/cgit/gnulib.git/tree/m4 into build/autoconf so that iconv.m4 can be used without error on Ubuntu or other platforms.
import m4_ax_compile_check_sizeof.m4 from autoconf archive