crt: Add link to _pei386_runtime_relocator GNU LD bug

Signed-off-by: LIU Hao <lh_mouse@126.com>

mingw-w64-crt/crt/pseudo-reloc.c

diff --git a/mingw-w64-crt/crt/pseudo-reloc.c b/mingw-w64-crt/crt/pseudo-reloc.c
index d6eb089..e8526b0 100644
--- a/mingw-w64-crt/crt/pseudo-reloc.c
+++ b/mingw-w64-crt/crt/pseudo-reloc.c
@@ -480,7 +480,7 @@
      }
 }
 
-__attribute__((used)) /* required due to bug in gcc / ld */
+__attribute__((used)) /* required due to GNU LD bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30343 */
 void
 _pei386_runtime_relocator (void)
 {