This commit lets us perform make commands of the following form:
`make unit pkg=accounts` which will run all the tests in the specified
package. Or you can do `make unit pkg=accounts case=TestAccountStore` to
run a specific test in the specified package.
This commit lets us perform commands of the form: `make unit
tags=postgres` to add additional tags to the command. This will be
useful in a future where we, for example, want to run unit tests against
a specific DB backend.
This commit let's us specify commands of the form: `make unit
case=TestNameHere`. Note that this commit by itself is not very useful
in LiT since there are no tests in the main `terminal` package. A later
commit will let us set a package name too and then this will be more
useful.
Add a new COMPILE_TAGS environment variable that includes all the basic
set of tags that lit requires in order for compilation to succeed. Let
LND_RELEASE_TAGS then extend these flags.
This will let us expand the testing_flags.mk file later without needing
to use the LND_RELEASE_TAGS variable there.
