Set CMake project version based on config.inc

Currently we set the CBMC version in config.inc.

It would be useful to have this information in our CMakeLists.txt as
well (especially for e.g. CPack packaging), and to avoid duplication it
would be better to have it in just one place. It’s somewhat easier to
parse config.inc from CMake than doing it the other way round (and we
already do it in src/util/CMakeLists.txt anyway), we do it here.

Author: hannes-steffenhagen-diffblue

CMakeLists.txt

@@ -1,6 +1,16 @@
 cmake_minimum_required(VERSION 3.2)
 
-project(CBMC)
+
+# Grab the current CBMC version from config.inc
+file(
+  STRINGS src/config.inc CBMC_VERSION
+  REGEX "CBMC_VERSION = (.*)")
+string(REGEX REPLACE "CBMC_VERSION = (.*)" "\\1" CBMC_VERSION ${CBMC_VERSION})
+
+project(CBMC VERSION ${CBMC_VERSION})
+
+# when config.inc changes we’ll need to reconfigure to check if the version changed
+set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/src/config.inc")
 
 find_program(CCACHE_PROGRAM ccache)
 if(CCACHE_PROGRAM)