From: Julian Ospald <hasufell@gentoo.org>
Date: Wed Jul 11 19:00:02 UTC 2012
Subject: build system

make DATA_INSTALL_DIR and game paths compatible with absolute paths

--- CMakeLists.txt
+++ CMakeLists.txt
@@ -27,7 +27,11 @@
 set(BINDIR  "games"             CACHE STRING "Directory from CMAKE_INSTALL_PREFIX where game executable will be installed.")
 set(DATADIR "share/games/flare" CACHE STRING "Directory from CMAKE_INSTALL_PREFIX where game data files will be installed.")
 
-add_definitions(-DDATA_INSTALL_DIR="${CMAKE_INSTALL_PREFIX}/${DATADIR}")
+If(NOT IS_ABSOLUTE "${DATADIR}")
+	add_definitions(-DDATA_INSTALL_DIR="${CMAKE_INSTALL_PREFIX}/${DATADIR}")
+Else(NOT IS_ABSOLUTE "${DATADIR}")
+	add_definitions(-DDATA_INSTALL_DIR="${DATADIR}")
+EndIf(NOT IS_ABSOLUTE "${DATADIR}")
 
 # Detect missing dependencies
 
@@ -163,10 +167,10 @@
 # installing to the proper places
 install(PROGRAMS
   ${CMAKE_CURRENT_BINARY_DIR}/flare
-  DESTINATION ${CMAKE_INSTALL_PREFIX}/${BINDIR})
+  DESTINATION ${BINDIR})
 install(DIRECTORY
   "${CMAKE_CURRENT_SOURCE_DIR}/mods"
-  DESTINATION ${CMAKE_INSTALL_PREFIX}/${DATADIR})
+  DESTINATION ${DATADIR})
 install(FILES
   "${CMAKE_CURRENT_BINARY_DIR}/flare.desktop"
   DESTINATION ${CMAKE_INSTALL_PREFIX}/share/applications)