[PATCH, GCC/ARM, 1/10] Fix -mcmse check in libgcc

[PATCH, GCC/ARM, 1/10] Fix -mcmse check in libgcc

This patch is part of a patch series to add support for Armv8.1-M
Mainline Security Extensions architecture.

Code to detect whether cmse.c can be buit with -mcmse checks the output
of host GCC when invoked with -mcmse. However, an error from the
compiler does not prevent some minimal output so this always holds true.

2020-01-16  Mihail-Calin Ionescu  <mihail.ionescu@arm.com>
2020-01-16  Thomas Preud'homme  <thomas.preudhomme@arm.com>

	* config/arm/t-arm: Check return value of gcc rather than lack of
	output.