Use _LDADD instead of _LDFLAGS for libraries

Signed-off-by: Morten Hustveit <mortehu@google.com>
Depend on libx11 1.4 rather than 1.5

Signed-off-by: Morten Hustveit <mortehu@google.com>
configre.ac: Add GLEW dependency

The GL Extension Wrangler makes it very easy to support multiple versions of
OpenGL.

Signed-off-by: Morten Hustveit <mortehu@google.com>
Use shaders instead of fixed pipeline

Signed-off-by: Morten Hustveit <mortehu@google.com>