Add wxGCC_WARNING_{SUPPRESS,RESTORE} macros and use them for -Wfloat-equal.

Suppress the warnings about comparing floating point values for equality in
wxWidgets headers when the user code is compiled with -Wfloat-equal (at least
when using g++ 4.6 or later).

Closes #14895.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73280 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/any.h

@@ -912,6 +912,8 @@ public:
     WXANY_IMPLEMENT_INT_EQ_OP(wxLongLong_t, wxULongLong_t)
 #endif
 
+    wxGCC_WARNING_SUPPRESS(float-equal)
+
     bool operator==(float value) const
     {
         if ( !wxAnyValueTypeImpl<float>::IsSameClass(m_type) )
@@ -932,6 +934,8 @@ public:
                 (wxAnyValueTypeImpl<double>::GetValue(m_buffer));
     }
 
+    wxGCC_WARNING_RESTORE(float-equal)
+
     bool operator==(bool value) const
     {
         if ( !wxAnyValueTypeImpl<bool>::IsSameClass(m_type) )