Support both the global post-process and the per-compiler post-process

lib/compile.js

@@ -254,7 +254,10 @@ Compile.prototype.compile = function (source, compiler, options, filters) {
     var compileToAsmPromise = tempFileAndDirPromise.then(function (info) {
         var inputFilename = info.inputFilename;
         var dirPath = info.dirPath;
-        var postProcess = compilerInfo.postProcess;
+        var postProcess = [compilerProps("postProcess"), compilerInfo.postProcess];
+        postProcess = postProcess.filter(function (x) {
+            return x;
+        });
         var outputFilename = path.join(dirPath, 'output.S');
         if (compilerInfo.options) {
             options = options.concat(compilerInfo.options.split(" "));
@@ -296,9 +299,9 @@ Compile.prototype.compile = function (source, compiler, options, filters) {
                     result.asm = "<No output: generated assembly was too large (" + stat.size + " > " + maxSize + " bytes)>";
                     return result;
                 }
-                if (postProcess) {
+                if (postProcess.length) {
                     return new Promise(function (resolve) {
-                        child_process.exec('cat "' + outputFilename + '" | ' + postProcess,
+                        child_process.exec('cat "' + outputFilename + '" | ' + postProcess.join(" | "),
                             {maxBuffer: maxSize},
                             function (err, data) {
                                 if (err)