[X11] Fixed SGI_swap_control query
authorthefiddler <stapostol@gmail.com>
Sun, 27 Apr 2014 23:29:34 +0000 (01:29 +0200)
committerthefiddler <stapostol@gmail.com>
Sun, 27 Apr 2014 23:29:34 +0000 (01:29 +0200)
commit0f920fb2051ea03082a4ec772f5b78ba6a537460
treeefa56f3604bf5d3a6ec48175f8a634ac504f50ac
parent168713aecfb980928fe7d90c86b1a5c70643edf3
[X11] Fixed SGI_swap_control query

GLX can return valid function pointer to unsupported functions.
We need to check for extension support in addition to the
function pointer.

Fixes crash on OpenSUSE 13.1 in VirtualBox.
Source/OpenTK/Platform/X11/X11GLContext.cs