prog/glsl: fix Makefile for samplers_array.

The rule added in 488b3c4d1bc3d830477180759a42dbaf8f5801b0 does not use the
right INCDIR, breaking the build when GL isn't installed in the default include
paths.

7.5 branch only fix, already fixed in master by rewriting the Makefile
(ceb9459ed5e63207defa5d715958c2757933272f)

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
1 file changed