Avoid run-time warnings for OS X version checks under 10.10+.

Remove UMAGetSystemVersion() function calling which produced the following
warning on the console for every call:

WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.4 instead
of 10.10.4. Use NSProcessInfo's operatingSystemVersion property to get correct
system version number.*

Replace UMAGetSystemVersion with wxPlatformInfo::CheckOSVersion() which
internally uses wxGetOSVersion, which uses Gestalt calls not resulting in this
runtime warning.

Closes https://github.com/wxWidgets/wxWidgets/pull/55

include/wx/osx/core/private.h

@@ -54,8 +54,6 @@
 // wxBase part of it).
 #include <Carbon/Carbon.h>
 
-WXDLLIMPEXP_BASE long UMAGetSystemVersion() ;
-
 void WXDLLIMPEXP_CORE wxMacStringToPascal( const wxString&from , unsigned char * to );
 wxString WXDLLIMPEXP_CORE wxMacMakeStringFromPascal( const unsigned char * from );
 

src/osx/cocoa/power.mm

@@ -15,6 +15,7 @@
 
 #include "wx/power.h"
 #include "wx/atomic.h"
+#include "wx/platinfo.h"
 #include "wx/osx/private.h"
 
 #include <IOKit/pwr_mgt/IOPMLib.h>
@@ -37,7 +38,7 @@ bool UpdatePowerResourceUsage(wxPowerResourceKind kind, const wxString& reason)
             cfreason = wxString("User Activity");
 
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_9
-        if ( UMAGetSystemVersion() >= 0x1090 )
+        if ( wxPlatformInfo::Get().CheckOSVersion(10, 9) )
         {
             // Use NSProcessInfo for 10.9 and newer
             if ( !g_processInfoActivity )
@@ -82,7 +83,7 @@ bool UpdatePowerResourceUsage(wxPowerResourceKind kind, const wxString& reason)
     {
         // Release power assertion
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_9
-        if ( UMAGetSystemVersion() >= 0x1090 )
+        if ( wxPlatformInfo::Get().CheckOSVersion(10, 9) )
         {
             // Use NSProcessInfo for 10.9 and newer
             if ( g_processInfoActivity )

src/osx/cocoa/utils.mm

@@ -11,6 +11,7 @@
 #include "wx/wxprec.h"
 
 #include "wx/utils.h"
+#include "wx/platinfo.h"
 
 #ifndef WX_PRECOMP
     #include "wx/intl.h"
@@ -346,7 +347,7 @@ void wxBell()
     ProcessSerialNumber psn = { 0, kCurrentProcess };
     TransformProcessType(&psn, kProcessTransformToForegroundApplication);
     
-    if ( UMAGetSystemVersion() >= 0x1090 )
+    if ( wxPlatformInfo::Get().CheckOSVersion(10, 9) )
     {
         [[NSRunningApplication currentApplication] activateWithOptions:
          (NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)];

src/osx/core/utilsexc_base.cpp

@@ -55,18 +55,6 @@ wxSocketManager *wxOSXSocketManagerCF = NULL;
 
 #if ( !wxUSE_GUI && !wxOSX_USE_IPHONE ) || wxOSX_USE_COCOA_OR_CARBON
 
-// have a fast version for mac code that returns the version as a return value
-
-long UMAGetSystemVersion()
-{
-    static SInt32 sUMASystemVersion = 0 ;
-    if ( sUMASystemVersion == 0 )
-    {
-        verify_noerr(Gestalt(gestaltSystemVersion, &sUMASystemVersion));
-    }
-    return sUMASystemVersion ;
-}
-
 // our OS version is the same in non GUI and GUI cases
 wxOperatingSystemId wxGetOsVersion(int *majorVsn, int *minorVsn)
 {

src/osx/window_osx.cpp

@@ -34,6 +34,7 @@
     #include "wx/menuitem.h"
     #include "wx/treectrl.h"
     #include "wx/listctrl.h"
+    #include "wx/platinfo.h"
 #endif
 
 #include "wx/tooltip.h"
@@ -2215,7 +2216,7 @@ bool wxWindowMac::MacHasScrollBarCorner() const
             if ( frame )
             {
                 // starting from 10.7 there are no resize indicators anymore
-                if ( (frame->GetWindowStyleFlag() & wxRESIZE_BORDER) && UMAGetSystemVersion() < 0x1070)
+                if ( (frame->GetWindowStyleFlag() & wxRESIZE_BORDER) && !wxPlatformInfo::Get().CheckOSVersion(10, 7) )
                 {
                     // Parent frame has resize handle
                     wxPoint frameBottomRight = frame->GetScreenRect().GetBottomRight();