I always build with --enable-compile-warnings=error so any compiler warning results in build failure. No special options beyond that.
Right. I do that too, and never saw an error. Your compiler must be warning on more things than mine. Here's my build commandline (copied from Jim nearly 2 years ago, and pretty much unchanged since):
./autogen.sh --with-qemu-user=qemu --with-qemu-group=qemu --enable-compile-warnings=error --prefix=/usr --libdir=/usr/lib64 --disable-nls CFLAGS="-g -Wformat -Wformat-security -Winit-self -Wall -Wpointer-arith -Wextra -Wshadow -Wcast-align -Wwrite-strings -Winline -Wno-sign-compare -Wp,-D_FORTIFY_SOURCE=2 -Dlint"
My command line is just autogen.sh --system --enable-compile-warnings=error --enable-debug=yes or if I need to debug something more seriously, I use autogen.sh --system --enable-compile-warnings=error --enable-debug=yes CFLAGS=-g to get rid of the default -O2. I noticed you don't have -O2 in your CFLAGS, which might be the issue here. While -g is much better than -g -O2 when you actually start debugging, gcc does not issue some warnings when it compiles without optimizations :-( Jirka