buildx.sh: utilize all available CPUs when compiling

xorg/X11R7.6/buildx.sh

@@ -149,7 +149,7 @@ make_it()
 
     # make module
     if [ ! -e cookies/$mod_name.made ]; then
-        if ! make -C build_dir/$mod_name
+        if ! make -j $NPROC -C build_dir/$mod_name
         then
             echo ""
             echo "make failed for module $mod_name"
@@ -267,6 +267,10 @@ if [ ! -d cookies ]; then
     fi
 fi
 
+if ! NPROC=`nproc`; then
+    NPROC=1
+fi
+
 while IFS=: read mod_file mod_dir mod_args
 do
     mod_args=`eval echo $mod_args`