MINGW patch by Csaba Halasz, reworked by me to avoid breaking MSVC or Cygwin build

src/GUI/gui_funcs.cxx

@@ -54,7 +54,9 @@
 #  include <simgear/screen/win32-printer.h>
 #  include <simgear/screen/GlBitmaps.h>
 #endif
-
+#ifdef __MINGW32__
+#include <shellapi.h>
+#endif
 #include "gui.h"
 
 using std::string;

src/Input/fgjs.cxx

@@ -28,7 +28,7 @@
 
 #include <simgear/compiler.h>
 
-#ifdef _MSC_VER
+#if defined( _MSC_VER ) || defined( __MINGW32__ )
 #  include <Winsock2.h>
 #endif
 

src/Main/bootstrap.cxx

@@ -141,7 +141,7 @@ int main ( int argc, char **argv ) {
     // Ignore floating-point exceptions on FreeBSD
     signal(SIGFPE, SIG_IGN);
 #endif
-#ifndef _MSC_VER
+#if !defined( _MSC_VER ) && !defined( __MINGW32__ )
     signal(SIGPIPE, SIG_IGN);
 #endif
 

src/Main/fg_init.cxx

@@ -581,7 +581,7 @@ bool fgInitConfig ( int argc, char **argv ) {
     }
 
     SGPropertyNode autosave;
-#ifdef _MSC_VER
+#if defined( _MSC_VER ) || defined( __MINGW32__ )
     char *envp = ::getenv( "APPDATA" );
     if (envp != NULL ) {
         SGPath config( envp );

src/Network/native_ctrls.cxx

@@ -36,8 +36,10 @@
 #include "native_ctrls.hxx"
 
 // FreeBSD works better with this included last ... (?)
-#if defined(WIN32) && !defined(__CYGWIN__)
+#if defined( _MSC_VER )
 #  include <windows.h>
+#elif defined( __MINGW32__ )
+#  include <Winsock2.h>
 #else
 #  include <netinet/in.h>	// htonl() ntohl()
 #endif

src/Network/native_fdm.cxx

@@ -39,8 +39,10 @@
 #include "native_fdm.hxx"
 
 // FreeBSD works better with this included last ... (?)
-#if defined(WIN32) && !defined(__CYGWIN__)
+#if defined( _MSC_VER )
 #  include <windows.h>
+#elif defined( __MINGW32__ )
+#  include <Winsock2.h>
 #else
 #  include <netinet/in.h>	// htonl() ntohl()
 #endif

utils/GPSsmooth/UGear_main.cxx

@@ -2,7 +2,7 @@
 #  include <config.h>
 #endif
 
-#ifndef _MSC_VER
+#if !defined( _MSC_VER ) && !defined( __MINGW32__ )
 #  include <strings.h>		// for bzero()
 #else
 #  define bzero(a,b) memset(a,0,b)