This patch extends the fix for PR53633 to include static functions,
which were giving a bogus -Wreturn-type warning for C but not for C++.

2019-07-18  Richard Sandiford  <richard.sandiford@arm.com>

gcc/c/
	PR c/53633
	* c-decl.c (finish_function): Check targetm.warn_func_return
	before issuing a -Wreturn-type warning.

gcc/testsuite/
	* c-c++-common/pr53633-2.c: New test.

From-SVN: r273568