libpsl: patch to reference the Windows-native stat [ci skip]

Upstream should fix this issue.

I consider this a libpsl portability issue that came to the surface
when mingw-w64 13 reshuffled its POSIX stat functions, by redirecting them
to intrinsics which are missing from earlier mingw-w64 versions. Thus
making binaries build with mingw-w64 v13 incompatible with v12.

Libraries may be better off calling the native Windows stat functions
listed here:

https://learn.microsoft.com/cpp/c-runtime-library/reference/stat-functions

LibreSSL also references the POSIX stat on Windows from its
`RAND_write_file()` API, causing the same issue, but curl doesn't call
this function, and thus isn't causing an actual issue in this use-case.

Reported-by: Morten / Mac-Fly
Reported-by: JackCarterSmith
Bug: https://curl.se/mail/lib-2025-10/0007.html
Fixes curl/curl#19516

Follow-up to add9e25

Author: vszakats

libpsl.sh

@@ -48,6 +48,11 @@ _VER="$1"
       echo "! Error: Our local PSL database filename is leaking into the libpsl code."
       exit 1
     fi
+    # Fix to use the Windows-native stat function to avoid mingw-w64 v13
+    # mapping the POSIX 'stat' one used in libpsl to an intrinsic and breaking
+    # interoperability with earlier mingw-w64 versions.
+    # This shall really be fixed upstream in libpsl.
+    [ "${_OS}" = 'win' ] && echo '#define stat _stati64' >> "${gencsrc}"
   fi
 
   mkdir -p "${_BLDDIR}"