windows: use _tzname instead of tzname

tzname is a POSIX variable, WIN32 has prefixed many POSIX variables
with "_". While Mingw64 supports both, UCRT64 emits a compiler warning
on the usage of "tzname".

This triggered a rather large clang-format update.

.github/workflows/builds.yml

@@ -2985,6 +2985,7 @@ jobs:
             make
             mingw-w64-ucrt-x86_64-cbindgen
             mingw-w64-ucrt-x86_64-jansson
+            mingw-w64-ucrt-x86_64-jq
             mingw-w64-ucrt-x86_64-libpcap
             mingw-w64-ucrt-x86_64-libtool
             mingw-w64-ucrt-x86_64-libyaml

src/util-strptime.c

@@ -384,7 +384,11 @@ recurse:
 				bp += 3;
 			} else {
                             ep = find_string(bp, &i,
+#ifdef _WIN32
+                                    (const char *const *)_tzname,
+#else
                                     (const char *const *)tzname,
+#endif
                                     NULL, 2);
                             if (ep != NULL) {
                                 tm->tm_isdst = i;