build: support ARM in makefile target 'binary'

Author: adammw

Makefile

@@ -216,8 +216,12 @@ endif
 ifeq ($(DESTCPU),x64)
 ARCH=x64
 else
+ifeq ($(DESTCPU),arm)
+ARCH=arm
+else
 ARCH=x86
 endif
+endif
 TARNAME=node-$(VERSION)
 TARBALL=$(TARNAME).tar.gz
 BINARYNAME=$(TARNAME)-$(PLATFORM)-$(ARCH)