analyzer: implement five new warnings for misuse of POSIX file descriptor APIs [PR106...

analyzer: implement five new warnings for misuse of POSIX file descriptor APIs [PR106003].

This patch adds a new state machine to the analyzer for checking usage of POSIX file descriptor
APIs with five new warnings.

It adds:
- check for FD leaks (CWE 775).
- check for double "close" of a FD (CWE-1341).
- check for read/write of a closed file descriptor.
- check whether a file descriptor was used without being checked for validity.
- check for read/write of a descriptor opened for just writing/reading.

gcc/ChangeLog:
	PR analyzer/106003
	* Makefile.in (ANALYZER_OBJS): Add sm-fd.o.
	* doc/invoke.texi:  Add -Wanalyzer-fd-double-close, -Wanalyzer-fd-leak,
	-Wanalyzer-fd-access-mode-mismatch, -Wanalyzer-fd-use-without-check,
	-Wanalyzer-fd-use-after-close.

gcc/analyzer/ChangeLog:
	PR analyzer/106003
	* analyzer.opt (Wanalyzer-fd-leak): New option.
	(Wanalyzer-fd-access-mode-mismatch): New option.
	(Wanalyzer-fd-use-without-check): New option.
	(Wanalyzer-fd-double-close): New option.
	(Wanalyzer-fd-use-after-close): New option.
	* sm.h (make_fd_state_machine): New decl.
	* sm.cc (make_checkers): Call make_fd_state_machine.
	* sm-fd.cc: New file.

gcc/testsuite/ChangeLog:
	PR analyzer/106003
	* gcc.dg/analyzer/fd-1.c: New test.
	* gcc.dg/analyzer/fd-2.c: New test.
	* gcc.dg/analyzer/fd-3.c: New test.
	* gcc.dg/analyzer/fd-4.c: New test.