intl: Fix an ISO C undefined behaviour.

ISO C 23 § 6.5.7.(10) has requirements for pointer subtraction.

Reported by <pizlonator> in https://github.com/pizlonator/fil-c/.

* gettext-runtime/intl/localealias.c (read_alias_file): Avoid invalid pointer
subtraction.

diff --git a/gettext-runtime/intl/localealias.c b/gettext-runtime/intl/localealias.c
index ff0f3f5042108bf61a9683c3c9bd485d23f974bb..7e0d4e7b56bab13bccb248ef038aef0a15b9658f 100644 (file)
--- a/gettext-runtime/intl/localealias.c
+++ b/gettext-runtime/intl/localealias.c
@@ -375,8 +375,10 @@ read_alias_file (const char *fname, int fname_len)
 
                        for (i = 0; i < nmap; i++)
                          {
-                           map[i].alias += new_pool - string_space;
-                           map[i].value += new_pool - string_space;
+                           map[i].alias =
+                             new_pool + (map[i].alias - string_space);
+                           map[i].value =
+                             new_pool + (map[i].value - string_space);
                          }
                      }