When pkgconf_fgetline encountered a backslash-continuation followed by a CR+LF line ending, it unconditionally pushed \n to the buffer before checking whether the continuation flag was set.
This left an embedded newline in the middle of the joined line, which the fragment parser then treated as whitespace (it was splitting -foo\-bar into -foo and -bar instead of -foo-bar.)

The \n push is now guarded by the same quoted check used for the plain \n case, making the \r handler consistent with the \n handler.

This manifests on Cygwin because git on Windows checks out files with CRLF endings by default, and Cygwin's fopen("r") does not translate \r\n to \n the way the MSVC CRT does.

I found this problem due to this test that was failing:
```
FAIL: multiline-folding-cflags.test
stderr:
================================================================================
stdout did not match:
  expected: [-foo-bar]
  actual: [-foo -bar]
```

Signed-off-by: moi15moi <moi15moismokerlolilol@gmail.com>