[SV 63333] Be more lenient when failing to create temporary files

[SV 63333] Be more lenient when failing to create temporary files

If make cannot create a temporary lock file for output sync, continue
without output sync enabled rather than dying.

However, if make cannot store a makefile from stdin to a temporary
file that is still a fatal error.

* misc.c (get_tmppath): Keep running on failure to generate a
temporary file name.
(get_tmpfd): Keep running on failure to get a temporary file.
(get_tmpfile): Keep running on failure to open a temporary file.
Ensure memory is freed if we return an error.
* posixos.c (os_anontmp): Keep running on failure to open an
anonymous temporary file.
* output.c (setup_tmpfile): Print an error on failure to create an
output sync lock file.
* main.c (main): Die on failure to store makefile from stdin to a
temporary file.
* tests/scripts/features/output-sync: Add tests.
* tests/scripts/features/temp_stdin: Ditto.