crt: Make tls_atexit run before __mingw_TLScallback

If libgcc was built with the win32 thread model, the emutls allocations
are freed via __mingw_TLScallback, which is hooked up at .CRT$XLD;
move the tls_atexit callback before this, to make sure TLS destructors
are run before their memory is freed by emutls.

Signed-off-by: Martin Storsjö <martin@martin.st>

mingw-w64-crt/crt/tls_atexit.c

diff --git a/mingw-w64-crt/crt/tls_atexit.c b/mingw-w64-crt/crt/tls_atexit.c
index 27ffb84..1241b56 100644
--- a/mingw-w64-crt/crt/tls_atexit.c
+++ b/mingw-w64-crt/crt/tls_atexit.c
@@ -148,4 +148,4 @@
   }
 }
 
-_CRTALLOC(".CRT$XLE") PIMAGE_TLS_CALLBACK __xl_e = (PIMAGE_TLS_CALLBACK) tls_callback;
+_CRTALLOC(".CRT$XLB") PIMAGE_TLS_CALLBACK __xl_b = (PIMAGE_TLS_CALLBACK) tls_callback;