glave: cleanup codegen of trace functionality

glave: cleanup codegen of trace functionality

* Splits declarations from implementations so that the implementations can be done in separate files - some codegen'd, some manually written.
* Many of the declarations are now marked as extern.
* I tried to remove as many of the big conditional blocks of code in the script that were specific to a single function. There are certainly still conditionals for small changes, but many of the calls should follow a consistent path through the script now.