configure: add -g to ASFLAGS when debug is enabled

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@19804 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

configure

@@ -2384,7 +2384,7 @@ check_header X11/extensions/XShm.h      &&
 check_func XOpenDisplay -lX11           &&
 check_func XShmCreateImage -lX11 -lXext
 
-enabled debug && add_cflags -g"$debuglevel"
+enabled debug && add_cflags -g"$debuglevel" && add_asflags -g"$debuglevel"
 
 # add some useful compiler flags if supported
 check_cflags -Wdeclaration-after-statement