search for: add_cflag

...mmit this issue slipped my mind. Since gcc-4.2 and later seems to be C99 and a lot of earlier compilers still exist I suggest that the vorbis build be patched to add the required warning flag wherever it is available. The following patch does the following: - Add an m4 directory containing the add_cflag.m4 macro which allows configure to test for the existance of a warning flag and add it to CFLAGS if it does exist. - Add AC_ADD_CFLAGS([-Wdeclaration-after-statement]) to the appropriate place in configure.in. - Include the m4 directory in Makefile.am and fiddle configure.ac and...