Fixes another failing test to pass on BigEndian.

Initial patch by Robin Dapp.

Reviewed-on: https://github.com/dlang/dmd/pull/9684

gcc/testsuite/ChangeLog:

2019-04-24  Iain Buclaw  <ibuclaw@gdcproject.org>

	* gdc.test/README.gcc: New file.

From-SVN: r270536