This is in preparation for making upb_def capable
of parsing binary descriptors directly.
We leave upb/descriptor/descriptor.upbdefs.* in
place for now, because upb/descriptor/reader.*
still depends on it.
Also removed a bit of cruft from the codegen.
There are a number of tweaks to get this to work:
- The #include dependence graph wasn't quite complete, and I had to add
a few #includes to get the tool to work.
- I had to change a number of symbol names to avoid conflicts between
'static' definitions in different .c files. This could be avoided if
the tool were smart enough to rename static symbols to have unique
prefixes instead, but (i) this requires semantic understanding of C,
and (ii) the macro-defined static functions (e.g., handlers for
primitive types in several places) would probably trip this up.
Verified that the resulting upb.h/upb.c compiles and doesn't have any
unresolved references.