Add support for launching windows ninja from cygwin.

ninja

Index: ninja
===================================================================
--- ninja	(revision 131317)
+++ ninja	(working copy)
@@ -6,6 +6,8 @@
   exec ninja-linux64 "$@"
 elif [ "${OS}" = "Darwin" ]; then
   exec ninja-mac "$@"
+elif [ "${OS}" = "CYGWIN_NT-6.1-WOW64" ]; then

[M-A Ruel, 2012/04/13 20:09:19]

Strictly speaking, WOW64 is not guaranteed but in practice, it's going to be
there. Can you do a proper "startswith" with [?

[scottmg, 2012/04/13 20:17:05]

Done.

+  exec cmd /c `cygpath -t windows $0`.bat "$@"

[M-A Ruel, 2012/04/13 20:09:19]

cmd.exe

[scottmg, 2012/04/13 20:17:05]

Done.

 else
   echo "Unsupported OS ${OS}"
   exit 1