gcc:
2017-09-03  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* common.opt (Wcast-align=strict): New warning option.
	* doc/invoke.texi: Document -Wcast-align=strict. 

c:
2017-09-03  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* c-typeck.c (build_c_cast): Implement -Wcast-align=strict.

cp:
2017-09-03  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* typeck.c (build_reinterpret_cast_1,
	build_const_cast_1): Implement -Wcast-align=strict.

testsuite:
2017-09-03  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* c-c++-common/Wcast-align.c: New test.