Please test gh832_has_mt

[Gerhard R.]

> Can you please also test gh823_has_mt if it can be merged?

I tried a native Windows build using Strawberry Perl + MSVC instead of
Cygwin, which failed:

First, auto::va_ptr dies because of the invocation

  cl  -D_CRT_SECURE_NO_DEPRECATE -DHASATTRIBUTE_DEPRECATED -wd4101
-DHASATTRIBUTE_NORETURN -wd4101 -DVA_TYPE_REGISTER-I./include -c
test_5836.c

which can be worked around via

diff --git a/lib/Parrot/Configure/Utils.pm b/lib/Parrot/Configure/Utils.pm
index 96d4ecf..2e8ef74 100644
--- a/lib/Parrot/Configure/Utils.pm
+++ b/lib/Parrot/Configure/Utils.pm
@@ -134,7 +134,7 @@ sub _build_compile_command {
         if @incs;
     }
     else {
-        $cc_args .= "-I./include -c";
+        $cc_args .= " -I./include -c";
     }
     return "$cc $ccflags $cc_args test_$$.c";
 }

Once that's done, your detection of mt.exe appears to work
(config_lib.pir contains an entry for has_mt), but I get the following
linking failure

  env.obj : error LNK2001: unresolved external symbol _environ

Gerhard R.