Add JOM generator support

Author: Yury Samkevich

src/lib.rs

@@ -632,7 +632,8 @@ impl Config {
                     cmd.arg("-G").arg(self.visual_studio_generator(&target));
                     false
                 } else {
-                    generator.as_ref().unwrap() == "NMake Makefiles"
+                    generator.as_ref().unwrap() == "NMake Makefiles" ||
+                        generator.as_ref().unwrap() == "NMake Makefiles JOM"
                 }
             };
             if !is_ninja && !using_nmake_generator {