CMake: use conventional method for setting version

- Using project() to set up the version is idiomatic for CMake
   and more standardised than doing it by hand. Do retain the
   RC flag, because that's used in other parts of versioning.

CMakeLists.txt

@@ -35,10 +35,10 @@
 # One special target is "show-version", which can be built
 # to obtain the version number from here.
 
-project( calamares C CXX )
-
-cmake_minimum_required( VERSION 3.2 )
-
+cmake_minimum_required( VERSION 3.2 FATAL_ERROR )
+project( calamares
+    VERSION 3.2.5
+    LANGUAGES C CXX )
 
 ### OPTIONS
 #
@@ -77,11 +77,11 @@ set( CALAMARES_APPLICATION_NAME  "Calamares" )
 set( CALAMARES_DESCRIPTION_SUMMARY
     "The distribution-independent installer framework" )
 
-set( CALAMARES_VERSION_MAJOR 3 )
-set( CALAMARES_VERSION_MINOR 2 )
-set( CALAMARES_VERSION_PATCH 5 )
-set( CALAMARES_VERSION_RC 1 )
-
+# Take settings from the project() command
+set( CALAMARES_VERSION_MAJOR ${calamares_VERSION_MAJOR} )
+set( CALAMARES_VERSION_MINOR ${calamares_VERSION_MINOR} )
+set( CALAMARES_VERSION_PATCH ${calamares_VERSION_PATCH} )
+set( CALAMARES_VERSION_RC 0 )
 
 ### Transifex (languages) info
 #

src/libcalamares/CMakeLists.txt

@@ -1,5 +1,3 @@
-project( libcalamares CXX )
-
 add_definitions(
     ${QT_DEFINITIONS}
     -DQT_SHARED

src/libcalamaresui/CMakeLists.txt

@@ -1,5 +1,3 @@
-project( libcalamaresui CXX )
-
 set( calamaresui_SOURCES
     modulesystem/CppJobModule.cpp
     modulesystem/Module.cpp