All-in-one build command

`./make-linux` clones and builds:

- arrow
- brotli
- lz4
- parquet
- snappy
- zlib
- zstd
- this project

as a statically linked binary. Two Boost libs are still pulled in as
shared libs, should probably fix that, too, for ultimate portability.

tests/test-non-existent

@@ -6,7 +6,7 @@ set -euo pipefail
 load_nonexistent() {
   cat <<EOF
 .echo on
-.load parquet/libparquet
+.load build/linux/libparquet
 .testcase notfound
 .bail on
 CREATE VIRTUAL TABLE test USING parquet('$root/doesnotexist.parquet');