[binutils-gdb] ada-lex: Ignore warnings about register keyword

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT d1435379df189d1c358ebd9776af8824a9158533 ***

Author: Simon Marchi <simon.marchi@ericsson.com>
Branch: master
Commit: d1435379df189d1c358ebd9776af8824a9158533

ada-lex: Ignore warnings about register keyword

Some older versions of flex (such as the one shipped with macOS) generate
code that use the register keyword, which clang warns about.  This patch
makes the compiler ignore those warnings for the portion of the code
generated by flex.

gdb/ChangeLog:

	* common/diagnostics.h (DIAGNOSTIC_IGNORE_DEPRECATED_REGISTER):
	New macro.
	* ada-lex.l: Ignore deprecated register warnings.