bug#6715: 24.0.50; [PATCH] Cygwin build should use pre-crt0.c

[Ken Brown]

The conclusion of

  http://lists.gnu.org/archive/html/emacs-devel/2010-07/msg00398.html

was that the Cygwin build of Emacs should use pre-crt0.c instead of 
ecrt0.c.  The following patch accomplishes this:

--- configure.in.orig   2010-07-12 10:39:38.000000000 -0400
+++ configure.in        2010-07-23 17:01:00.468750000 -0400
@@ -1060,7 +1060,7 @@
 case $opsys in
   cygwin )
     LIB_MATH=
-    START_FILES='ecrt0.o'
+    START_FILES='pre-crt0.o'
     ;;
   darwin )
     ## Adding -lm confuses the dynamic linker, so omit it.

I'm sending this as a bug report so it doesn't get forgotten.  Please 
apply it to the trunk.

Thanks.

Ken