Fixes autotools warnings.
Moved generic compiler options to AM_CFLAGS. MPD_CFLAGS/MPD_LIBS will hopefully fade away one day, in favor of more fine-grained variables.
Previously, it was not possible to check for e.g. "-std=c99".
needed for compatibility with older gcc. Also, threw in some warnings for things I find offensive (declaration-after-statement, shadow) git-svn-id: https://svn.musicpd.org/mpd/trunk@7299 09075e82-0dd4-0310-85a5-a0d7c8717e4f
Max Kellermann