Add ARM build support (#360)

docs/api.md

@@ -97,7 +97,7 @@ The alternative values `win32` (for Windows) or `darwin`, `mac` (for OSX) can al
 -a, --arch <value>
 ```
 
-Processor architecture, automatically determined based on the current OS. Can be overwritten by specifying either `ia32` or `x64`.
+Processor architecture, automatically determined based on the current OS. Can be overwritten by specifying either `ia32`, `x64` or `armv7l`.
 
 #### [electron-version]
 

src/cli.js

@@ -21,7 +21,7 @@ if (require.main === module) {
     })
     .option('-n, --name <value>', 'app name')
     .option('-p, --platform <value>', '\'osx\', \'linux\' or \'windows\'')
-    .option('-a, --arch <value>', '\'ia32\' or \'x64\'')
+    .option('-a, --arch <value>', '\'ia32\' or \'x64\' or \'armv7l\'')
     .option('-e, --electron-version <value>', 'electron version to package, without the \'v\', see https://github.com/atom/electron/releases')
     .option('--no-overwrite', 'do not override output directory if it already exists, defaults to false')
     .option('-c, --conceal', 'packages the source code within your app into an archive, defaults to false, see http://electron.atom.io/docs/v0.36.0/tutorial/application-packaging/')

src/infer/inferOs.js

@@ -11,7 +11,7 @@ function inferPlatform() {
 
 function inferArch() {
   const arch = os.arch();
-  if (arch !== 'ia32' && arch !== 'x64') {
+  if (arch !== 'ia32' && arch !== 'x64' && arch !== 'arm') {
     throw new Error(`Incompatible architecture ${arch} detected`);
   }
   return arch;