This reverts commit 2019658b86.
Reason for revert: broke builds where makefiles were using M4 without depending upon it
Change-Id: I18304246e7a8a8f8c2620dd2c65ed77acd256be2
This allows setting per-module make variables earlier in the build,
particularly for prebuilt_build_tool users like LEX/M4/BISON. I moved
filegroup over because it's a simpler common interface, but it doesn't
strictly need it.
With this, the last user of the hardcoded cc.m4Cmd variable is gone.
Test: Inspect out/soong/make_vars-*.mk, out/soong/late-*.mk
Test: treehugger
Change-Id: I195b688131feac0c100c338a0749368aa5d50f4f
cc_prebuilt_binary doesn't work well for host tools because they'll
often be using their own versions of shared libraries that may not be
compatible with what we build.
So add a module type that allows genrules to use one of these prebuilts
as a tool. Like other prebuilts, we'll use the source module if we have
it, or the prebuilt otherwise.
It supports adding extra dependencies for shared libraries or other data
files that are necessary to run the tool. Any genrules using the tool
will be rerun if any of the dependencies change.
Bug: 128690776
Test: treehugger (builds one-true-awk with bison)
Change-Id: I82c26be1c3c9fe6cab42892ddea339c301c0b316
