fix build on raspberry pi

`-march=native` does not work on Raspberry Pi 3 with old gcc compilers. This is a bug in gcc
and has been fixed in later versions. Raspbian comes with gcc 4.9. Using
`-mcpu=cortex-a53` instead of `-march=native` would also work, but
because proper arch detection did not work before this PR
https://github.com/cjdelisle/cjdns/pull/1075 just disabling it again for
arm seems like an easy fix.

node_build/make.js

@@ -29,7 +29,7 @@ var GCC = process.env['CC'];
 var CFLAGS = process.env['CFLAGS'];
 var LDFLAGS = process.env['LDFLAGS'];
 
-var NO_MARCH_FLAG = ['ppc', 'ppc64'];
+var NO_MARCH_FLAG = ['arm', 'ppc', 'ppc64'];
 
 if (GCC) {
     // Already specified.