Look for MAKE_OPTS to override options sent to make to address build failures on some systems

bin/ruby-build

@@ -127,9 +127,11 @@ build_package() {
 
 build_package_standard() {
   local package_name="$1"
-
+  if [ -z "${MAKE_OPTS+defined}" ]; then
+    MAKE_OPTS="-j 2"
+  fi
   { ./configure --prefix="$PREFIX_PATH" $CONFIGURE_OPTS
-    make -j 2
+    make $MAKE_OPTS
     make install
   } >&4 2>&1
 }