rename 'debug' interface to 'logging' interface

It's not really about debugging, but about generic logging...
diff --git a/include/osmocore/logging.h b/include/osmocore/logging.h
new file mode 100644
index 0000000..93f18a0
--- /dev/null
+++ b/include/osmocore/logging.h
@@ -0,0 +1,130 @@
+#ifndef _OSMOCORE_LOGGING_H
+#define _OSMOCORE_LOGGING_H
+
+#include <stdio.h>
+#include <stdint.h>
+#include <osmocore/linuxlist.h>
+
+#define LOG_MAX_CATEGORY	32
+#define LOG_MAX_CTX		8
+#define LOG_MAX_FILTERS	8
+
+#define DEBUG
+
+#ifdef DEBUG
+#define DEBUGP(ss, fmt, args...) logp(ss, __FILE__, __LINE__, 0, fmt, ## args)
+#define DEBUGPC(ss, fmt, args...) logp(ss, __FILE__, __LINE__, 1, fmt, ## args)
+#else
+#define DEBUGP(xss, fmt, args...)
+#define DEBUGPC(ss, fmt, args...)
+#endif
+
+#define static_assert(exp, name) typedef int dummy##name [(exp) ? 1 : -1];
+
+char *hexdump(const unsigned char *buf, int len);
+void logp(unsigned int subsys, char *file, int line, int cont, const char *format, ...) __attribute__ ((format (printf, 5, 6)));
+
+/* new logging interface */
+#define LOGP(ss, level, fmt, args...) \
+	logp2(ss, level, __FILE__, __LINE__, 0, fmt, ##args)
+#define LOGPC(ss, level, fmt, args...) \
+	logp2(ss, level, __FILE__, __LINE__, 1, fmt, ##args)
+
+/* different levels */
+#define LOGL_DEBUG	1	/* debugging information */
+#define LOGL_INFO	3
+#define LOGL_NOTICE	5	/* abnormal/unexpected condition */
+#define LOGL_ERROR	7	/* error condition, requires user action */
+#define LOGL_FATAL	8	/* fatal, program aborted */
+
+#define LOG_FILTER_ALL	0x0001
+
+struct log_category {
+	uint8_t loglevel;
+	uint8_t enabled;
+};
+
+struct log_info_cat {
+	const char *name;
+	const char *color;
+	const char *description;
+	uint8_t loglevel;
+	uint8_t enabled;
+};
+
+/* log context information, passed to filter */
+struct log_context {
+	void *ctx[LOG_MAX_CTX+1];
+};
+
+struct log_target;
+
+typedef int log_filter(const struct log_context *ctx,
+		       struct log_target *target);
+
+struct log_info {
+	/* filter callback function */
+	log_filter *filter_fn;
+
+	/* per-category information */
+	const struct log_info_cat *cat;
+	unsigned int num_cat;
+};
+
+struct log_target {
+        struct llist_head entry;
+
+	int filter_map;
+	void *filter_data[LOG_MAX_FILTERS+1];
+
+	struct log_category categories[LOG_MAX_CATEGORY+1];
+	uint8_t loglevel;
+	int use_color:1;
+	int print_timestamp:1;
+
+	union {
+		struct {
+			FILE *out;
+		} tgt_stdout;
+
+		struct {
+			int priority;
+		} tgt_syslog;
+
+		struct {
+			void *vty;
+		} tgt_vty;
+	};
+
+        void (*output) (struct log_target *target, const char *string);
+};
+
+/* use the above macros */
+void logp2(unsigned int subsys, unsigned int level, char *file,
+	   int line, int cont, const char *format, ...)
+				__attribute__ ((format (printf, 6, 7)));
+void log_init(const struct log_info *cat);
+
+/* context management */
+void log_reset_context(void);
+int log_set_context(uint8_t ctx, void *value);
+
+/* filter on the targets */
+void log_set_all_filter(struct log_target *target, int);
+
+void log_set_use_color(struct log_target *target, int);
+void log_set_print_timestamp(struct log_target *target, int);
+void log_set_log_level(struct log_target *target, int log_level);
+void log_parse_category_mask(struct log_target *target, const char* mask);
+int log_parse_level(const char *lvl);
+int log_parse_category(const char *category);
+void log_set_category_filter(struct log_target *target, int category,
+			       int enable, int level);
+
+/* management of the targets */
+struct log_target *log_target_create(void);
+struct log_target *log_target_create_stderr(void);
+void log_add_target(struct log_target *target);
+void log_del_target(struct log_target *target);
+
+#endif /* _OSMOCORE_LOGGING_H */