linux-x86: Set emulator path using a "noop" script without argument.

This will fix issue where emulator is used doing:

  COMMAND ${CMAKE_CROSSCOMPILING_EMULATOR} /path/to/prog arg1 arg2

Prior to this commit, it wasn't working because the following command
was used:

  /bin/sh -c /path/to/prog arg1 arg2

linux-x86/i686-linux-gnu-noop.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec "$@"