A cmake generator in bazel is introduced allowing to import the Swift
extractor as a CMake project while keeping Bazel files as the source of
truth for the build.
Using the CMake project:
* requires bazel and clang to be installed and available on the command
line
* does not require a previous bazel build, however
* will require a CMake reconfiguration for changes to generated code
(like changes to the schema)
This checks in the trapgen script generating trap entries in C++.
The codegen suite has been slightly reorganized, moving the templates
directory up one level and chopping everything into smaller bazel
packages. Running tests is now done via
```
bazel run //swift/codegen/test
```
With respect to the PoC, the nested `codeql::trap` namespace has been
dropped in favour of a `Trap` prefix (or suffix in case of entries)
within the `codeql` namespace. Also, generated C++ code is not checked
in in git any more, and generated during build. Finally, labels get
printed in hex in the trap file.
`TrapLabel` is for the moment only default-constructible, so only one
single label is possible. `TrapArena`, that is responsible for creating
disjoint labels will come in a later commit.
* fixed 5.0.0 as bazel version
* made dependencies better loadable
* moved `//swift/install` to `//swift:create-extractor-pack` (following
the clearer ruby naming)
* renamed `extractor_pack` to `extractor-pack` for consistency with Ruby
This adds a first dummy extractor for swift.
Running `bazel run //swift:install` will create an `extractor_pack`
directory in `swift`. From that moment providing `--search-path=swift`
will pick up the extractor.
