Refactor the code to find scripts.

Hopefully fixes scripts on Windows too, but untested yet.
diff --git a/cli/cli_diff.cpp b/cli/cli_diff.cpp
index d9d6257..0bd1b31 100644
--- a/cli/cli_diff.cpp
+++ b/cli/cli_diff.cpp
@@ -31,7 +31,7 @@
 #include "cli.hpp"
 #include "os_string.hpp"
 #include "os_process.hpp"
-#include "trace_tools.hpp"
+#include "trace_resource.hpp"
 
 static const char *synopsis = "Identify differences between two traces.";
 
@@ -81,11 +81,7 @@
     file1 = argv[i];
     file2 = argv[i+1];
 
-#define CLI_DIFF_TRACEDIFF_COMMAND "tracediff.sh"
-
-    os::String command = trace::findFile("scripts/" CLI_DIFF_TRACEDIFF_COMMAND,
-                 APITRACE_SCRIPTS_INSTALL_DIR "/" CLI_DIFF_TRACEDIFF_COMMAND,
-                                       true);
+    os::String command = trace::findScript("tracediff.sh");
 
     char* args[4];