cmake: fix ENABLE_TRACE parameter being too strict

In order to check whether tracing support should be turned on, we check
whether ENABLE_TRACE equals "ON". This is being much too strict, as
CMake will also treat "on", "true", "yes" and others as true-ish, but
passing them will disable tracing support now.

Fix the issue by simply removing the STREQUAL, which will cause CMake to
do the right thing automatically.

src/CMakeLists.txt

@@ -28,7 +28,7 @@ SET(LIB_INSTALL_DIR lib CACHE PATH "Where to install libraries to.")
 SET(INCLUDE_INSTALL_DIR include CACHE PATH "Where to install headers to.")
 
 # Enable tracing
-IF (ENABLE_TRACE STREQUAL "ON")
+IF(ENABLE_TRACE)
 	SET(GIT_TRACE 1)
 ENDIF()
 ADD_FEATURE_INFO(tracing GIT_TRACE "tracing support")