Add GZIP (gzip)

Modules/FindCygwin.cmake

@@ -8,6 +8,11 @@ FIND_PATH(CYGWIN_INSTALL_PATH
   "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Cygnus Solutions\\Cygwin\\mounts v2\\/;native]"
 )
 
+FIND_PROGRAM(GZIP
+   gzip
+   ${CYGWIN_INSTALL_PATH}/bin
+)
+
 FIND_PROGRAM(MV
    mv
    ${CYGWIN_INSTALL_PATH}/bin