Add DDB_NUMSYM option which in addition to the symbolic representation

also prints the actual numerical value of the symbol in question.

Users of addr2line(1) will be less proficient in hex arithmetic as a
consequence.

This amongst other things means that traceback lines change from:
   siointr1(c4016800,c073bda0,0,c06b699c,69f) at siointr1+0xc5
to
   siointr1(c4016800,c073bda0,0,c06b699c,69f) at 0xc062b0bd = siointr1+0xc5

I made this an option to avoid bikesheds.
~
~
~

sys/conf/NOTES

@@ -233,6 +233,11 @@ options 	SYSVMSG
 #
 options 	DDB
 
+#
+# print the actual numerical value of symbols in addition to the
+# symbolic representation
+options		DDB_NUMSYM
+
 #
 # Use direct symbol lookup routines for ddb instead of the kernel linker
 # ones, so that symbols (mostly) work before the kernel linker has been

sys/conf/options

@@ -84,6 +84,7 @@ CY_PCI_FASTINTR
 DDB
 DDB_NOKLDSYM	opt_ddb.h
 DDB_TRACE
+DDB_NUMSYM	opt_ddb.h
 DDB_UNATTENDED
 GDB_REMOTE_CHAT	opt_ddb.h
 GDBSPEED	opt_ddb.h

sys/ddb/db_sym.c

@@ -37,6 +37,8 @@ __FBSDID("$FreeBSD$");
 #include <ddb/ddb.h>
 #include <ddb/db_sym.h>
 
+#include <opt_ddb.h>
+
 /*
  * Multiple symbol tables
  */
@@ -308,7 +310,11 @@ db_printsym(off, strategy)
 		db_printf("%#lr", (unsigned long)off);
 		return;
 	}
+#ifdef DDB_NUMSYM
+	db_printf("%#lr = %s", (unsigned long)off, name);
+#else
 	db_printf("%s", name);
+#endif
 	if (d)
 		db_printf("+%+#lr", (long)d);
 	if (strategy == DB_STGY_PROC) {