lib517: use `LL` 64-bit literals & re-enable a test case (`time_t`)

Suffix two 64-bit `time_t` test literals with `LL` to make them compile
with mingw-w64 x86_64 in C89 (the default) mode. Possibly other old gcc
compilers are affected (e.g. mips gcc 4.9.4, power gcc 15.1.0), but
could not pinpoint the exact rules. This also fixes a compiler warning
and test failure with MSVC, allowing to re-enable a disabled test case.

`LL` is not C89, but used in the code before this patch, which tells
it's safe to use.

Also display expected / actual timestamp values as `curl_off_t` instead
of `long`, making them work with 64-bit timestamps.

This was triggered by this issue seen while testing mingw-w64 gcc 4.8.1:
```
tests/libtest/lib517.c:147:5: error: this decimal constant is unsigned only in ISO C90
     {"Sun, 06 Nov 2044 08:49:37 GMT", (time_t) 2362034977 },
     ^
```
Ref: https://github.com/curl/curl/actions/runs/16540378828/job/46780712313?pr=18010#step:12:32

Closes #18032

diff --git a/tests/libtest/lib517.c b/tests/libtest/lib517.c
index cefc42f7fdff4f672ed7f509939ac2f368c0c899..5324d6378f404b11eb43e1811c50342d25aca1b2 100644 (file)
--- a/tests/libtest/lib517.c
+++ b/tests/libtest/lib517.c
@@ -144,23 +144,20 @@ static CURLcode test_lib517(char *URL)
     {"Thu, 31-Dec-1969 23:59:58 GMT", -2 },
     {"Thu, 31-Dec-1969 23:59:59 GMT", 0 }, /* avoids -1 ! */
 #if SIZEOF_TIME_T > 4
-    {"Sun, 06 Nov 2044 08:49:37 GMT", (time_t) 2362034977 },
+    {"Sun, 06 Nov 2044 08:49:37 GMT", (time_t)2362034977LL },
     {"Sun, 06 Nov 3144 08:49:37 GMT", 37074617377 },
 #ifndef HAVE_TIME_T_UNSIGNED
-#if 0
-    /* causes warning on MSVC */
-    {"Sun, 06 Nov 1900 08:49:37 GMT", -2182259423 },
-#endif
+    {"Sun, 06 Nov 1900 08:49:37 GMT", (time_t)-2182259423LL },
     {"Sun, 06 Nov 1800 08:49:37 GMT", -5337933023 },
     {"Thu, 01-Jan-1583 00:00:00 GMT", -12212553600 },
-#endif
+#endif /* HAVE_TIME_T_UNSIGNED */
     {"Thu, 01-Jan-1499 00:00:00 GMT", -1 },
 #else
     {"Sun, 06 Nov 2044 08:49:37 GMT", -1 },
-#endif
+#endif /* SIZEOF_TIME_T > 4 */
 #ifndef HAVE_TIME_T_UNSIGNED
     {"Sun, 06 Nov 1968 08:49:37 GMT", -36342623 },
-#endif
+#endif /* !HAVE_TIME_T_UNSIGNED */
     { NULL, 0 }
   };
 
@@ -172,8 +169,10 @@ static CURLcode test_lib517(char *URL)
   for(i = 0; dates[i].input; i++) {
     time_t out = curl_getdate(dates[i].input, NULL);
     if(out != dates[i].output) {
-      curl_mprintf("WRONGLY %s => %ld (instead of %ld)\n",
-                   dates[i].input, (long)out, (long)dates[i].output);
+      curl_mprintf("WRONGLY %s => %" CURL_FORMAT_CURL_OFF_T
+                   " (instead of %" CURL_FORMAT_CURL_OFF_T ")\n",
+                   dates[i].input,
+                   (curl_off_t)out, (curl_off_t)dates[i].output);
       error++;
     }
   }