'lineinfo' in prototypes saved as differences instead of absolute

values, so that the array can use bytes instead of ints, reducing
its size. (A new array 'abslineinfo' is used when line differences
do not fit in a byte.)

ltests.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.c,v 2.219 2017/06/09 16:48:44 roberto Exp roberto $
+** $Id: ltests.c,v 2.220 2017/06/12 14:21:44 roberto Exp roberto $
 ** Internal Module for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
@@ -537,7 +537,7 @@ static char *buildop (Proto *p, int pc, char *buff) {
   Instruction i = p->code[pc];
   OpCode o = GET_OPCODE(i);
   const char *name = luaP_opnames[o];
-  int line = getfuncline(p, pc);
+  int line = luaG_getfuncline(p, pc);
   sprintf(buff, "(%4d) %4d - ", line, pc);
   switch (getOpMode(o)) {
     case iABC: