Save location information of symbol definitions

Now, object files save the file name and line number where each global
symbol is defined.

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

include/link/mylink.h

@@ -89,6 +89,8 @@ struct sSymbol {
 	SLONG nSectionID;	/* internal to object.c */
 	struct sSection *pSection;
 	SLONG nOffset;
+	char *pzFileName; /* Source file where the symbol was defined. */
+	ULONG nFileLine; /* Line where the symbol was defined. */
 };
 
 enum ePatchType {