Define bb_xgetlarg as a standard interface for extracting
numbers from getopt which includes careful error checking.
 -Erik
diff --git a/include/libbb.h b/include/libbb.h
index c057ce4..8cb72de 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -121,6 +121,7 @@
 	  void* userData);
 
 extern int parse_mode( const char* s, mode_t* theMode);
+extern long bb_xgetlarg(char *arg, int base, long lower, long upper);
 
 extern int get_kernel_revision(void);