GCN libgcc.

GCN libgcc.

This patch contains the GCN port of libgcc.

2019-01-17  Andrew Stubbs  <ams@codesourcery.com>
	    Kwok Cheung Yeung  <kcy@codesourcery.com>
	    Julian Brown  <julian@codesourcery.com>
	    Tom de Vries  <tom@codesourcery.com>

	libgcc/
	* config.host: Recognize amdgcn*-*-amdhsa.
	* config/gcn/crt0.c: New file.
	* config/gcn/lib2-divmod-hi.c: New file.
	* config/gcn/lib2-divmod.c: New file.
	* config/gcn/lib2-gcn.h: New file.
	* config/gcn/sfp-machine.h: New file.
	* config/gcn/t-amdgcn: New file.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@268021 138bc75d-0d04-0410-961f-82ee72b054a4