re PR pch/13675 (#including a precompiled header more than once in the same unit fails)
PR pch/13675
* files.c (struct _cpp_file): Remove pch field.
(pch_open_file): Don't set file->pch, just file->pchname.
(should_stack_file): After pfile->cb.read_pch call
free pchname and clear pchname, don't close file->fd.
Test file->pchname instead of file->pch. Don't close fd after cb.
(_cpp_stack_include): Test file->pchname instead of file->pch.
* c-pch.c (c_common_read_pch): On error close (fd) resp. fclose (f).
From-SVN: r133790