[Bug preprocessor/84583] New: -fdirectives-only does not handle CRLF properly

[boris at kolpackov dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84583

            Bug ID: 84583
           Summary: -fdirectives-only does not handle CRLF properly
           Product: gcc
           Version: 7.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: boris at kolpackov dot net
  Target Milestone: ---

Created attachment 43515
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43515&action=edit
reproducing source code

The attached archive contains foo.c (as well as foo.p and foo.i, for reference)
that if preprocessed with -fdirectives-only on Windows (for example, using the
MinGW build of GCC) produces incorrect result:

gcc.exe -E -fdirectives-only -o foo.p foo.c
gcc.exe -E -fpreprocessed -fdirectives-only -x c foo.p >foo.i

foo.c:7:16: warning: missing terminating " character
foo.c:9:30: warning: missing terminating " character

It appears that in the first invocation GCC replaces each LF character with the
CRLF sequence thus ending up with CRCRLF sequences.

Will be happy to test a patch.