curl_setup: include _mingw.h

Prior to this change _mingw.h needed to be included in each unit before
evaluating __MINGW{32,64}_xxx_VERSION macros since it defines them. It
is included only in some mingw headers (eg stdio.h) and not others
(eg windows.h) so it's better to explicitly include it once.

Closes https://github.com/curl/curl/pull/9036

lib/config-win32.h

@@ -453,9 +453,6 @@
 
 /* mingw-w64, mingw using >= MSVCR80, and visual studio >= 2005 (MSVCR80)
    all default to 64-bit time_t unless _USE_32BIT_TIME_T is defined */
-#ifdef __MINGW32__
-#  include <_mingw.h>
-#endif
 #if defined(__MINGW64_VERSION_MAJOR) || \
     (defined(__MINGW32__) && (__MSVCRT_VERSION__ >= 0x0800)) || \
     (defined(_MSC_VER) && (_MSC_VER >= 1400))

lib/curl_setup.h

@@ -28,6 +28,11 @@
 #define CURL_NO_OLDIES
 #endif
 
+/* define mingw version macros, eg __MINGW{32,64}_{MINOR,MAJOR}_VERSION */
+#ifdef __MINGW32__
+#include <_mingw.h>
+#endif
+
 /*
  * Disable Visual Studio warnings:
  * 4127 "conditional expression is constant"

lib/vtls/schannel.h

@@ -62,7 +62,6 @@ CURLcode Curl_verify_certificate(struct Curl_easy *data,
 #ifdef EXPOSE_SCHANNEL_INTERNAL_STRUCTS
 
 #ifdef __MINGW32__
-#include <_mingw.h>
 #ifdef __MINGW64_VERSION_MAJOR
 #define HAS_MANUAL_VERIFY_API
 #endif