turbojpeg.c: Fix Windows build

Broken by previous commit.  Although turbojpeg.c no longer needs
tjutil.h on Un*x, it still needs to include that file on Windows in
order to use snprintf() and strcasecmp() (which, on Windows, are macros
that wrap _snprintf_s() and stricmp().)

turbojpeg.c

@@ -39,6 +39,7 @@
 #include <setjmp.h>
 #include <errno.h>
 #include "./turbojpeg.h"
+#include "./tjutil.h"
 #include "transupp.h"
 #include "./jpegcomp.h"
 #include "./cdjpeg.h"