lib: unstupidify thread debug information

the library's thread scheduling functions keep track of the thread
function's name, so far so good.  However, copying the compiler-provided
constant into a buffer inside the thread structure is plain useless.
Also, strip_funcname() was trying to support something that never
happens.

Instead, let's use some bytes here to track where threads are scheduled
from.  Another commit will print that information on crashes.

Ripping out useless stuff:  -64 bytes in the thread structure
Re-add as const ptr:         +8 bytes
Extra debug info:           +12 bytes

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/lib/thread.h b/lib/thread.h
index dbf5f25..a088b47 100644
--- a/lib/thread.h
+++ b/lib/thread.h
@@ -64,9 +64,6 @@
 
 typedef unsigned char thread_type;
 
-/* ISO C99 maximum function name length is 63 */
-#define FUNCNAME_LEN	64
-
 /* Thread itself. */
 struct thread
 {
@@ -85,7 +82,9 @@
   int index;			/* used for timers to store position in queue */
   struct timeval real;
   struct cpu_thread_history *hist; /* cache pointer to cpu_history */
-  char funcname[FUNCNAME_LEN];
+  const char *funcname;
+  const char *schedfrom;
+  int schedfrom_line;
 };
 
 struct cpu_thread_history 
@@ -100,7 +99,7 @@
   struct time_stats cpu;
 #endif
   thread_type types;
-  char funcname[FUNCNAME_LEN];
+  const char *funcname;
 };
 
 /* Clocks supported by Quagga */
@@ -165,15 +164,17 @@
 #define THREAD_WRITE_OFF(thread)  THREAD_OFF(thread)
 #define THREAD_TIMER_OFF(thread)  THREAD_OFF(thread)
 
-#define thread_add_read(m,f,a,v) funcname_thread_add_read(m,f,a,v,#f)
-#define thread_add_write(m,f,a,v) funcname_thread_add_write(m,f,a,v,#f)
-#define thread_add_timer(m,f,a,v) funcname_thread_add_timer(m,f,a,v,#f)
-#define thread_add_timer_msec(m,f,a,v) funcname_thread_add_timer_msec(m,f,a,v,#f)
-#define thread_add_event(m,f,a,v) funcname_thread_add_event(m,f,a,v,#f)
-#define thread_execute(m,f,a,v) funcname_thread_execute(m,f,a,v,#f)
+#define debugargdef  const char *funcname, const char *schedfrom, int fromln
+
+#define thread_add_read(m,f,a,v) funcname_thread_add_read(m,f,a,v,#f,__FILE__,__LINE__)
+#define thread_add_write(m,f,a,v) funcname_thread_add_write(m,f,a,v,#f,__FILE__,__LINE__)
+#define thread_add_timer(m,f,a,v) funcname_thread_add_timer(m,f,a,v,#f,__FILE__,__LINE__)
+#define thread_add_timer_msec(m,f,a,v) funcname_thread_add_timer_msec(m,f,a,v,#f,__FILE__,__LINE__)
+#define thread_add_event(m,f,a,v) funcname_thread_add_event(m,f,a,v,#f,__FILE__,__LINE__)
+#define thread_execute(m,f,a,v) funcname_thread_execute(m,f,a,v,#f,__FILE__,__LINE__)
 
 /* The 4th arg to thread_add_background is the # of milliseconds to delay. */
-#define thread_add_background(m,f,a,v) funcname_thread_add_background(m,f,a,v,#f)
+#define thread_add_background(m,f,a,v) funcname_thread_add_background(m,f,a,v,#f,__FILE__,__LINE__)
 
 /* Prototypes. */
 extern struct thread_master *thread_master_create (void);
@@ -181,27 +182,29 @@
 
 extern struct thread *funcname_thread_add_read (struct thread_master *, 
 				                int (*)(struct thread *),
-				                void *, int, const char*);
+				                void *, int, debugargdef);
 extern struct thread *funcname_thread_add_write (struct thread_master *,
 				                 int (*)(struct thread *),
-				                 void *, int, const char*);
+				                 void *, int, debugargdef);
 extern struct thread *funcname_thread_add_timer (struct thread_master *,
 				                 int (*)(struct thread *),
-				                 void *, long, const char*);
+				                 void *, long, debugargdef);
 extern struct thread *funcname_thread_add_timer_msec (struct thread_master *,
 				                      int (*)(struct thread *),
-				                      void *, long, const char*);
+				                      void *, long, debugargdef);
 extern struct thread *funcname_thread_add_event (struct thread_master *,
 				                 int (*)(struct thread *),
-				                 void *, int, const char*);
+				                 void *, int, debugargdef);
 extern struct thread *funcname_thread_add_background (struct thread_master *,
                                                int (*func)(struct thread *),
 				               void *arg,
 				               long milliseconds_to_delay,
-					       const char *funcname);
+					       debugargdef);
 extern struct thread *funcname_thread_execute (struct thread_master *,
                                                int (*)(struct thread *),
-                                               void *, int, const char *);
+                                               void *, int, debugargdef);
+#undef debugargdef
+
 extern void thread_cancel (struct thread *);
 extern unsigned int thread_cancel_event (struct thread_master *, void *);
 extern struct thread *thread_fetch (struct thread_master *, struct thread *);