Include build date/time and bitness in the About dialog


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4609 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e67feb4..3a3b23a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -63,6 +63,7 @@
 endif()
 
 message(STATUS "VERSION = ${VERSION}, BUILD = ${BUILD}")
+add_definitions(-D__BUILD__="${BUILD}")
 
 if(NOT DEFINED BUILD_WINVNC)
   if(MSVC)