File fix-build.patch of Package cdogs-sdl

Index: cdogs-sdl-1.4.0/CMakeLists.txt
===================================================================
--- cdogs-sdl-1.4.0.orig/CMakeLists.txt
+++ cdogs-sdl-1.4.0/CMakeLists.txt
@@ -147,6 +147,9 @@ if(NOT DEFINED CDOGS_DATA_DIR)
 	endif()
 endif()
 message("Data dir is ${CDOGS_DATA_DIR}")
+if(NOT DEFINED DATA_INSTALL_DIR)
+  set(DATA_INSTALL_DIR "${CDOGS_DATA_DIR}")
+endif()
 if(WIN32)
 	set(CDOGS_CFG_DIR "C-Dogs SDL/")
 else()
@@ -199,7 +202,6 @@ elseif(APPLE)
 	set(INSTALL_PREFIX "cdogs-sdl")
 else()
 	set(LIB_EXTENSION ".so")
-	set(DATA_INSTALL_DIR ".")
 endif()
 
 # Since Debian wants games binaries in /usr/games