[Bug libquadmath/68665] New: fails to link quad math functions even though cygquadmath-0.dll is present

[mc1soft at yahoo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68665

            Bug ID: 68665
           Summary: fails to link quad math functions even though
                    cygquadmath-0.dll is present
           Product: gcc
           Version: 4.9.3
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P3
         Component: libquadmath
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mc1soft at yahoo dot com
  Target Milestone: ---

Created attachment 36891
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36891&action=edit
zip archive with source, headers, temp files

When using Cygwin with GCC 4.9.3-1 and libquadmath0 4.9.3-1 under Win XP SP3
the following error occurs:

$ gcc -o test128a test128a.c -save-temps

test128a.o:test128a.c:(.text+0x10f): undefined reference to `quadmath_snprintf'
collect2: error: ld returned 1 exit status

I have #include <quadmath.h> in a C source, and the __float128 type works, but
not the functions (which I can test by removing all the functions).

I found a dll cygquadmath-0.dll which definitely has these functions in it.  It
is in 3 places in the Cygwin installation.  Additionally, I copied it to
Windows\System, but that did not help.  

The source is attached.  The headers are also attached even though they are
from the Cygwin distribution, not mine.  All requested intermediate files are
attached.