Put the internal library path first so that we can 
build with an older webkitgtk4 package installed.

Index: Source/cmake/OptionsCommon.cmake
--- Source/cmake/OptionsCommon.cmake.orig
+++ Source/cmake/OptionsCommon.cmake
@@ -221,6 +221,9 @@ elseif (NOT ENABLE_ASSERTS)
     WEBKIT_PREPEND_GLOBAL_COMPILER_FLAGS(-DASSERT_ENABLED=0)
 endif ()
 
+# make sure that the internal library dir is the first in the path
+link_directories("${CMAKE_BINARY_DIR}/lib")
+
 # Check whether features.h header exists.
 # Including glibc's one defines __GLIBC__, that is used in Platform.h
 WEBKIT_CHECK_HAVE_INCLUDE(HAVE_FEATURES_H features.h)