Added 1GB swap to build forge

Makefile

 all: rustc forgecode clean
 
 forgecode:
+	dd if=/dev/zero of=swap bs=1048576 count=1024
+	chmod 600 swap
+	mkswap swap
+	swapon swap
+
 	mkdir .cargo
 	mkdir -p /root/.cargo
 	mount --bind .cargo /root/.cargo
@@ -15,6 +20,9 @@ forgecode:
 	rm -rf /root/.cargo
 	rm -rf .cargo
 
+	swapoff swap
+	rm -rf swap
+
 rustc:
 	$(MAKE) -C ../rustc temporary