E3-453: Remove EPICSVERSION loop

See merge request e3/e3-require!89

This is necessary for the following reason: the previous mechanism used an
eval/call combination that required SUBS and TMPS to be exported on a previous
pass through. This allowed us to use `vpath` for each specific file in order
to locate the correct source files.

In order to avoid that, we add two new ingredients:
* `VPATH` instead of `vpath`, since it allows us to have variables
  that are expanded later
* `.SECONDEXPANSION`, which allows a target (`db_internal`, in this case) to
  perform a second variable expansion at the _end_ of the pass through.

All of this is necessary because the typical module makefile looks like:
```
include driver.makefile

SUBS += ...
```
i.e. `SUBS` and `TMPS` are defined _after_ the inclusion of driver.makefile. If
we don't want to force a re-write of every single module makefile, we needed
to do some of the above changes.

Note that there is something surprising here: `EXCLUDE_ARCHS` _filters_
the architectures (i.e. runs it as %arch%), while `ARCH_FILTER` matches
exactly. This is exactly backwards from what the names suggest.

However, I am leaving this as is for the time being since there are
possibly existing wrappers that use these two variables in this way; a
further investigation should be done to ensure that we can improve this
in some sense. If we make such a change, we should regard it as breaking.

E3-879: driver.Makefile: Add check for inconsistent versions between dependencies

See merge request e3/e3-require!88

In a dependency chain like B->A->C and also B->C where A needs a version
of C different than B the build should fail.
This commit adds this check during dependency treatment on the built
target.

E3-847: Apply all the patches

See merge request e3/e3-require!87

E3-822: Register dependencies for expanded db files

See merge request e3/e3-require!86

This follows the same pattern as the .d files generated during compilation; the
.d files are generated as a side effect of generating the output file, and we
then include them all at build-time to register the correct dependencies. See
line 634 of driver.makefile.

E3-670: Propose linters

See merge request e3/e3-require!85

Primarily since we appear to compile require with C and not C++

This reverts commit 9b59288d.