Add some debug printout macros

include/logging.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2019 - 2020 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#pragma once
+
+#include <stdio.h>
+
+#ifdef NDEBUG
+#define log_debug(...)
+#else
+#define log_debug(fmt, ...) \
+	fprintf(stderr, "%s:%d: " fmt, __FILE__, __LINE__, ## __VA_ARGS__)
+#endif
+
+#define log_error(...) \
+	fprintf(stderr, "ERROR: " __VA_ARGS__)