[Bug d/88127] Many gdc.dg testsuite failures due to undefined reference to qsort_r

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88127

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
Patch at [1].

[1] https://gcc.gnu.org/ml/gcc-patches/2019-02/msg00120.html