Fix program args not having a space

When inputs.size() is 1 and we have programArgs,
we wind up squashing those two values together.

Be pessimistic and always add the space in.

hphp/compiler/compiler.cpp

@@ -943,7 +943,8 @@ int runTarget(const CompilerOptions &po) {
   }
   cmd += po.outputDir + '/' + po.program;
   cmd += string(" --file ") +
-    (po.inputs.size() == 1 ? po.inputs[0] : "") + po.programArgs;
+    (po.inputs.size() == 1 ? po.inputs[0] : "") +
+    " " + po.programArgs;
   Logger::Info("running executable: %s", cmd.c_str());
   ret = Util::ssystem(cmd.c_str());
   if (ret && ret != -1) ret = 1;