CMake: partial revert of updated versioning

- Keep the project() version as literal, drop the script-mode changes,
  to keep existing (weird?) build-and-packaging hacks working.
- Do switch to unified versioning-git-annotations CMake module,
  do drop the "rc" from version numbers.

CMakeLists.txt

@@ -40,23 +40,13 @@
 
 # TODO:3.3: Require CMake 3.12
 cmake_minimum_required( VERSION 3.3 FATAL_ERROR )
-
-set( CALAMARES_VERSION 3.2.40 )
-set( CALAMARES_RELEASE_MODE OFF )
-
-if ( CMAKE_SCRIPT_MODE_FILE )
-    include( ${CMAKE_CURRENT_LIST_DIR}/CMakeModules/ExtendedVersion.cmake )
-    set( CMAKE_SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR} )
-    extend_version( ${CALAMARES_VERSION} OFF _vshort _vlong )
-    message( "${_vlong}" )
-    return()
-endif()
-
 project( CALAMARES
-    VERSION ${CALAMARES_VERSION}
+    VERSION 3.2.40
     LANGUAGES C CXX
 )
 
+set( CALAMARES_VERSION_RC 1 )  # Set to 0 during release cycle, 1 during development
+
 ### OPTIONS
 #
 option( INSTALL_CONFIG "Install configuration files" OFF )
@@ -190,7 +180,6 @@ include( FeatureSummary )
 
 # Calamares Modules
 include( CMakeColors )
-include( ExtendedVersion )
 
 ### C++ SETUP
 #
@@ -505,21 +494,30 @@ add_feature_info( ExampleDistro ${mksquashfs_FOUND} "Create example-distro targe
 
 ### CALAMARES PROPER
 #
-#
+set( CALAMARES_VERSION ${CALAMARES_VERSION_MAJOR}.${CALAMARES_VERSION_MINOR}.${CALAMARES_VERSION_PATCH} )
-extend_version( "${CALAMARES_VERSION}" ${CALAMARES_RELEASE_MODE} CALAMARES_VERSION_SHORT CALAMARES_VERSION )
+# In rare cases we have hotfix-releases with a tweak
+if( CALAMARES_VERSION_TWEAK )
+    set( CALAMARES_VERSION "${CALAMARES_VERSION}.${CALAMARES_VERSION_TWEAK}" )
+endif()
+set( CALAMARES_VERSION_SHORT "${CALAMARES_VERSION}" )
 
-# Special target for displaying the version. In RC (might-be-release)
+# Additional info for non-release builds. The "extended" version information
-# builds, use the short version (3.x.y), otherwise show the long version.
+# with date and git information (commit, dirty status) is used only
-if ( CALAMARES_RELEASE_MODE )
+# by CalamaresVersionX.h, which is included by consumers that need a full
+# version number with all that information; normal consumers can include
+# CalamaresVersion.h with more stable numbers.
+if( NOT BUILD_RELEASE AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.git/" )
+    include( ExtendedVersion )
+    extend_version( "${CALAMARES_VERSION}" OFF CALAMARES_VERSION_SHORT CALAMARES_VERSION )
+endif()
+
+# Special target for not-RC (e.g. might-be-release) builds.
+# This is used by the release script to get the version.
+if ( CALAMARES_VERSION_RC EQUAL 0 )
     add_custom_target(show-version
         ${CMAKE_COMMAND} -E echo CALAMARES_VERSION=${CALAMARES_VERSION_SHORT}
         USES_TERMINAL
     )
-else()
-    add_custom_target(show-version
-        ${CMAKE_COMMAND} -E echo CALAMARES_VERSION=${CALAMARES_VERSION}
-        USES_TERMINAL
-    )
 endif()
 
 # enforce using constBegin, constEnd for const-iterators