Fix Cygwin 1.7 build.

Avoid using Cygwin sockets as our code assumes that we use WinSock API under
Windows currently (this might change in the future) by defining
__USE_W32_SOCKETS.

Use new, safer and more efficient cygwin_conv_path() function.

Use t_str() instead of fn_str() with Windows API taking file names, under
Cygwin they are different and using fn_str() is incorrect.

A few other minor fixes.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65057 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/filefn.cpp

@@ -64,11 +64,13 @@
     #include "wx/msw/mslu.h"
 
     // sys/cygwin.h is needed for cygwin_conv_to_full_win32_path()
+    // and for cygwin_conv_path()
     //
     // note that it must be included after <windows.h>
     #ifdef __GNUWIN32__
         #ifdef __CYGWIN__
             #include <sys/cygwin.h>
+            #include <cygwin/version.h>
         #endif
     #endif // __GNUWIN32__
 
@@ -1062,7 +1064,7 @@ wxCopyFile (const wxString& file1, const wxString& file2, bool overwrite)
     // instead of our code if available
     //
     // NB: 3rd parameter is bFailIfExists i.e. the inverse of overwrite
-    if ( !::CopyFile(file1.fn_str(), file2.fn_str(), !overwrite) )
+    if ( !::CopyFile(file1.t_str(), file2.t_str(), !overwrite) )
     {
         wxLogSysError(_("Failed to copy the file '%s' to '%s'"),
                       file1.c_str(), file2.c_str());
@@ -1505,11 +1507,19 @@ wxChar *wxDoGetCwd(wxChar *buf, int sz)
         // another example of DOS/Unix mix (Cygwin)
         wxString pathUnix = buf;
 #if wxUSE_UNICODE
+    #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+        cygwin_conv_path(CCP_POSIX_TO_WIN_W, pathUnix.mb_str(wxConvFile), buf, sz);
+    #else
         char bufA[_MAXPATHLEN];
         cygwin_conv_to_full_win32_path(pathUnix.mb_str(wxConvFile), bufA);
         wxConvFile.MB2WC(buf, bufA, sz);
+    #endif
 #else
+    #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+        cygwin_conv_path(CCP_POSIX_TO_WIN_A, pathUnix, buf, sz);
+    #else
         cygwin_conv_to_full_win32_path(pathUnix, buf);
+    #endif
 #endif // wxUSE_UNICODE
 #endif // __CYGWIN__
     }