build: Disable --disable-fuzz-binary for guix builds

Author: hebasto

contrib/guix/libexec/build.sh

@@ -204,7 +204,7 @@ fi
 ###########################
 
 # CONFIGFLAGS
-CONFIGFLAGS="--enable-reduce-exports --disable-bench --disable-gui-tests"
+CONFIGFLAGS="--enable-reduce-exports --disable-bench --disable-gui-tests --disable-fuzz-binary"
 case "$HOST" in
     *linux*) CONFIGFLAGS+=" --enable-glibc-back-compat" ;;
 esac