it looks like multi-chunks sorting stream is running, even though kernek side not yet.
Merge branch 'master' of https://github.com/kaigai/pg_strom
bugfix: pg_varchar_t gets accepted by pgfn_textcmp

because codegen generate individual pg_##NAME##_t data types,
OpenCL compiler considered pg_text_t and pg_varchar_t are
incompatible data types each other, even though they have
identical format and PostgreSQL assumes varlena variables
are mutuable.
This commit makes all the varlena types as alias of
pg_varlena_t, so compiler can handle them as same data type.