Remove ALLEGRO_DLL_SHORTVER unused variable.

The versioning in the cmake script could really be avoided without all
the magic regex. Applying VERSION when defining project(), cmake will
automatically apply version sematics and define variables such as
PROJECT_VERSION_(MAJOR|MINOR|PATCH|TWEAK). Will be done next commit.

Author: giladreich

CMakeLists.txt

@@ -53,7 +53,6 @@ option(WANT_STATIC_RUNTIME "Whether or not to link the C and C++ runtimes static
 
 set(ALLEGRO_VERSION 5.2.9)
 string(REGEX MATCH "^[0-9]+[.][0-9]+" ALLEGRO_SOVERSION ${ALLEGRO_VERSION})
-string(REPLACE "." "" ALLEGRO_DLL_SHORTVER ${ALLEGRO_SOVERSION})
 
 # Search in the `cmake' directory for additional CMake modules.
 list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)