Manually merge revision 939 from PRODUCTION_1_0_x.

cygwin-win32.h: New file. Declare get_current_win32_thread_id().

cygwin-win32.cxx: Ditto. Implement get_current_win32_thread_id().

threads.cxx: Use get_current_win32_thread_id() on Cygwin.

Makefile.am: Add new files.

*: Regenerate.

Author: wilx

aclocal.m4

@@ -13,8 +13,8 @@
 
 m4_ifndef([AC_AUTOCONF_VERSION],
   [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
-m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.67],,
-[m4_warning([this file was generated for autoconf 2.67.
+m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.68],,
+[m4_warning([this file was generated for autoconf 2.68.
 You have another version of autoconf.  It may work, but is not guaranteed to.
 If you have problems, you may need to regenerate the build system entirely.
 To do so, use the procedure documented by the package, typically `autoreconf'.])])