configure & compiler warning cleanup
- configure: Use
LT_INIT
from libtool 2 instead of deprecatedAC_PROG_LIBTOOL
- Quiet
-Wredundant-decls
fromxorg/os.h
fallbacks for new libc functions - Fix 24 of 24
-Wimplicit-fallthrough
warnings - Fix
-Wanalyzer-possible-null-argument
warning inATIDRIScreenInit