Fix some Windows compile issues, add JSON_EXPORT's, fix bogus character escapes, define __func__ and omit unistd.h if needed.

tests/test_util_file.c

@@ -6,7 +6,9 @@
 #include <string.h>
 #include <fcntl.h>
 #include <limits.h>
-#include <unistd.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif /* HAVE_UNISTD_H */
 #include <sys/types.h>
 #include <sys/stat.h>