Permit putting structs with anonymous and empty fields in the C header
file runtime.inc that is used to build the C runtime code. This is
required for upcoming 1.13 support, as the m struct has picked up an
anonymous field.
Doing this lets the C header contain all the type descriptor structs,
so start using those in the C code. This cuts the number of copies of
type descriptor definitions from 3 to 2.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/192343
From-SVN: r275227
Move the list of libgo, gotool, and check-target packages into
separate files, then read the file contents as part of the build
process on the fly. This is intended to enable other build tooling to
share the canonical list of target packages (avoid duplication).
Reviewed-on: https://go-review.googlesource.com/89515
libgo: revise rules for runtime.inc generation
Refactor code for generating runtime.inc: extract out the relevant
commands and place them in a separate shell script ("mkruntimeinc.sh").
Update rules to avoid generating macros whose names begin with "$",
such as "#define $sinkconst0 0".
Reviewed-on: https://go-review.googlesource.com/85955
From-SVN: r259863
