Handle VersionGeneration outside of the main CMakeFile

This is actually a good change: we used to write a new
CMake file in configure time just to move it outside of the
source to the build dir at compile time. Now this file is
pre-created and it's only moved.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

cmake/Modules/HandleVersionGeneration.cmake

@@ -0,0 +1,17 @@
+# Generate the ssrf-config.h every 'make'
+file(WRITE ${CMAKE_BINARY_DIR}/version.h.in
+"#define VERSION_STRING \"@VERSION_STRING@\"
+#define GIT_VERSION_STRING \"@GIT_VERSION_STRING@\"
+#define CANONICAL_VERSION_STRING \"@CANONICAL_VERSION_STRING@\"
+")
+
+file(COPY cmake/Modules/version.cmake
+    DESTINATION ${CMAKE_BINARY_DIR})
+
+add_custom_target(
+	version ALL COMMAND ${CMAKE_COMMAND} ${CMAKE_COMMAND}
+	-D SRC=${CMAKE_BINARY_DIR}/version.h.in
+	-D DST=${CMAKE_BINARY_DIR}/ssrf-version.h
+	-D CMAKE_SYSTEM_NAME=${CMAKE_SYSTEM_NAME}
+	-P ${CMAKE_BINARY_DIR}/version.cmake
+)