VISUALAGE OS/2 fixups needed for new Png lib.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@17527 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/png/png.c

@@ -144,7 +144,7 @@ png_zalloc(voidpf png_ptr, uInt items, uInt size)
 {
    png_uint_32 num_bytes = (png_uint_32)items * size;
    png_voidp ptr;
-   png_structp p=png_ptr;
+   png_structp p=(png_struct*)png_ptr;
    png_uint_32 save_flags=p->flags;
 
    p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;

src/png/pngconf.h

@@ -1241,6 +1241,20 @@ typedef z_stream FAR *  png_zstreamp;
 #endif
 #endif
 
+#if defined(__VISAGECPP__)
+/* I don't compile with this _System linkage for wxWindows */
+#  ifdef PNGAPI
+#    undef PNGAPI
+#  endif
+#  define PNGAPI _Optlink
+#  define PNG_IMPEXP
+#  define PNG_USE_LOCAL_ARRAYS
+#  ifdef PNG_USE_GLOBAL_ARRAYS
+#    undef PNG_USE_GLOBAL_ARRAYS
+#  endif
+extern const char png_libpng_ver[18];
+#endif
+
 #ifndef PNGAPI
 #  define PNGAPI
 #endif