Added a workaround for a bug in my graphics driver(?) whereby ...

glVertexArrayVertexAttribDivisorEXT was not defined. Not sure about the bindingindex parameter, re-used location, maybe that's bad.

Here's some of my glxinfo:
server glx vendor string: ATI
server glx version string: 1.4
client glx vendor string: ATI
client glx version string: 1.4
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: AMD Radeon HD 7800 Series  
OpenGL core profile version string: 4.3.12874 Core Profile Context 13.35.1005
OpenGL core profile shading language version string: 4.30
OpenGL version string: 4.4.12874 Compatibility Profile Context 13.35.1005
OpenGL shading language version string: 4.30

And from lspci:
05:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Pitcairn PRO [Radeon HD 7850] (prog-if 00 [VGA controller])
	Subsystem: Micro-Star International Co., Ltd. [MSI] Device 2733
	Flags: bus master, fast devsel, latency 0, IRQ 47
	Memory at e0000000 (64-bit, prefetchable) [size=256M]
	Memory at feb80000 (64-bit, non-prefetchable) [size=256K]
	I/O ports at e000 [size=256]
	[virtual] Expansion ROM at feb00000 [disabled] [size=128K]
	Capabilities: [48] Vendor Specific Information: Len=08 <?>
	Capabilities: [50] Power Management version 3
	Capabilities: [58] Express Legacy Endpoint, MSI 00
	Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
	Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
	Capabilities: [150] Advanced Error Reporting
	Capabilities: [270] #19
	Capabilities: [2b0] Address Translation Service (ATS)
	Capabilities: [2c0] #13
	Capabilities: [2d0] #1b
	Kernel driver in use: fglrx_pci