CMakeLists.txt: fix FTE_REVISON definition (#386)

Author: erysdren

CMakeLists.txt

@@ -17,15 +17,15 @@ INCLUDE_DIRECTORIES(
 	engine
 )
 
-IF (EXISTS ${CMAKE_SOURCE_DIR}/.svn AND "${FTE_REVISON}" STREQUAL "")
+IF (EXISTS ${CMAKE_SOURCE_DIR}/.svn AND NOT DEFINED FTE_REVISON)
 	EXECUTE_PROCESS(COMMAND
 		"svnversion"
 		WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
 		OUTPUT_VARIABLE FTE_REVISON
 		ERROR_QUIET OUTPUT_STRIP_TRAILING_WHITESPACE
 	)
 
-	IF (NOT "${FTE_REVISON}" STREQUAL "")
+	IF (DEFINED FTE_REVISON)
 		MESSAGE(STATUS "FTE SVN Revision ${FTE_REVISON}")
 		IF(FTE_REVISON MATCHES "M")
 			MESSAGE(STATUS "--- PRIVATE CHANGES DETECTED ---")
@@ -42,7 +42,7 @@ IF (EXISTS ${CMAKE_SOURCE_DIR}/.svn AND "${FTE_REVISON}" STREQUAL "")
 		ENDIF()
 	ENDIF()
 ENDIF()
-IF (EXISTS ${CMAKE_SOURCE_DIR}/.git AND "${FTE_REVISON}" STREQUAL "")
+IF (EXISTS ${CMAKE_SOURCE_DIR}/.git AND NOT DEFINED FTE_REVISON)
 	EXECUTE_PROCESS(COMMAND
 		git describe --always --long --dirty
 		WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"