Undef _T before including standard headers and redefine it later.

This change fixes the build of wxWidgets itself by undefining _T() before
including any standard headers and redefining it after including them.

See #10660.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@61871 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/afterstd.h

@@ -46,3 +46,26 @@
     #endif
 #endif
 
+/*
+    Redefine _T if we undefined it in wx/beforestd.h (see comment there about
+    why do we do it) and if we need it (we always do when building wx itself
+    and might also need when compiling the user code but this must be indicated
+    by the special wxNEEDS__T macro)
+ */
+#if defined(__SUNPRO_CC) || defined(__SUNPRO_C)
+    #if defined(WXBUILDING) || defined(wxNEEDS_T)
+        /*
+            Undefine _T in case it was defined in the standard header.
+         */
+        #undef _T
+
+        /*
+            And define it again in the same way as it's done in wx/wxchar.h.
+         */
+        #if wxUSE_UNICODE
+            #define _T(x) wxCONCAT_HELPER(L, x)
+        #else /* !Unicode */
+            #define _T(x) x
+        #endif /* Unicode/!Unicode */
+    #endif /* we need _T() to be defined */
+#endif /* defined(__SUNPRO_CC) || defined(__SUNPRO_C) */

include/wx/beforestd.h

@@ -63,3 +63,13 @@
     #pragma warning(disable:4786)
 #endif // VC++ < 7
 
+/*
+    Recent versions of Sun C++ compiler use _T in their standard headers and
+    our definition of it in wx/wxchar.h conflicts with them and breaks
+    compilation, so undefine _T before including them and redefine it back in
+    wx/afterstd.h if needed.
+ */
+#if defined(__SUNPRO_CC) || defined(__SUNPRO_C)
+    #undef _T
+#endif /* SUNCC */
+