Add a script to build a textured cube demo static binary

We introduce HAVE_NO_LIBMALI_BLOB define to compile this binary
without the dependency on libMali.so proprietary blob. If this
macro is defined, then just fail and return NULL instead of
compiling a shader.

This demo program needs two shader blobs: 'shader_v.mbs' and
'shader_f.mbs'. Which have to be obtained elsewhere (generated
by the offline shader compiler or by open source gpu tools).

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>