emv: fix false -Wstringop-overflow in AID list rule with AVX2

Building the client with -march=x86-64-v3 (the CentOS/RHEL 10
baseline) fails with gcc 14:

  src/emv/emvcore.c:211:24: error: writing 32 bytes into a region of
  size 22 [-Werror=stringop-overflow=]

gcc vectorizes the dash fill loop in aidlist_rule() into 32-byte
stores and loses the pos + 2 < dstlen bound. The bound was correct.
Compute the dash count with the same limit and fill it with memset,
so there is no vectorized loop store to mis-size. Output is unchanged.

Reported in #3671.

Co-Authored-By: Grok Bot <noreply@users.noreply.github.com>

CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file.
 This project uses the changelog in accordance with [keepchangelog](http://keepachangelog.com/). Please use this to write notable changes, which is not the same as git commit log...
 
 ## [unreleased][unreleased]
+- Fixed client build with `-march=x86-64-v3` (CentOS/RHEL 10 default) - false `-Wstringop-overflow` in the EMV AID list table (@r3wretrhy)
 - Changed `hf seos info` - now prints UID, ATQA, SAK, ATS, MIFARE Classic emulation, which SEOS AIDs answer and the known AIDs found (@antoniovazquezblanco)
 - Fixed `hf seos managekeys -p` - key table columns stay aligned for slots 10 and up (@antoniovazquezblanco)
 - Fixed `aidlist.json` - uppercased the SEOS, TeslaDAP and LA Tap AIDs (@antoniovazquezblanco)

client/src/emv/emvcore.c

@@ -207,9 +207,14 @@ static void aidlist_rule(char *dst, size_t dstlen, size_t w_aid, size_t w_prio,
 
     dst[pos++] = '+';
     for (size_t c = 0; c < 3; c++) {
-        for (size_t i = 0; (i < widths[c] + 2) && (pos + 2 < dstlen); i++) {
-            dst[pos++] = '-';
+        // memset, not a byte loop: gcc's AVX2 vectorized loop trips -Wstringop-overflow
+        size_t n = widths[c] + 2;
+        size_t room = (pos + 2 < dstlen) ? dstlen - pos - 2 : 0;
+        if (n > room) {
+            n = room;
         }
+        memset(dst + pos, '-', n);
+        pos += n;
         if (pos + 1 < dstlen) {
             dst[pos++] = '+';
         }