Fix EXEEXT for lock obj creation.
* src/Makefile.am (lock-obj-pub.native.h): Add EXEEXT for the executable gen-posix-lock-obj.
This change is from packaging work for Cygwin.
- Reported-by: Michael Haubenwallner <michael.haubenwallner@ssi-schaefer.com>
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>