targets as packages

[Sterling Hughes <st...@apache.org>]

Hey,

Recently there was a commit to make targets work like packages, instead 
of using a SQLite repository in the base of the application.

The goal here was to make it easier for people to:

a- reuse and redistribute targets
b- read the contents of a target and grep for them

In the new design, when I issue:

$ newt target create blinky_sim
Creating target blinky_sim
Target blinky_sim successfully created!
$ newt target show
blinky_sim
	arch=sim
	compiler_def=default
	name=blinky_sim
	vers=0.0.1


This creates a directory structure as follows:

$ ls
BRANCHING_STRATEGY	README.md		fs			net			scripts
LICENSE			app.yml			hw			pkg-list.yml		sys
NOTICE			compiler		libs			project			targets
$ ls targets/blinky_sim/pkg.yml
targets/blinky_sim/pkg.yml
$

With targets/blinky_sim/pkg.yml containing both the package directives, 
and the compiler directives:

$ cat targets/blinky_sim/pkg.yml
### Target: blinky_sim

pkg.arch: sim
pkg.bsp: hw/bsp/native
pkg.compiler_def: default
pkg.name: blinky_sim
pkg.vers: 0.0.1
$

I don't think this is correct.  I think there should be a file, called 
target.yml or <target-name>.yml, that contains a separate set of target 
variables.

There is a similar problem with compiler/sim/compiler.yml.  Where it 
looks like pkg.yml definitions are now hacked into compiler.yml:

$ more compiler/sim/osx-compiler.yml
<snip>

pkg.name: compiler/sim
pkg.vers: 0.8.0
pkg.description: Compiler definition for native gcc compiler.
pkg.author: sterling <st...@runtime.io>
pkg.homepage:
pkg.repository: 
https://git-wip-us.apache.org/repos/asf/incubator-mynewt-larva
pkg.keywords:
     - sim
     - compiler
     - gcc

compiler.path.cc: "/usr/local/bin/gcc-5"
compiler.path.archive: "ar"
compiler.path.objdump: "gobjdump"
compiler.path.objsize: "objsize"
compiler.path.objcopy: "gobjcopy"

compiler.flags.base: >
     -m32 -Wall -Werror -ggdb -O0 -DMN_OSX

compiler.flags.default: [compiler.flags.base]
compiler.flags.debug: [compiler.flags.base, -ggdb -O0]

compiler.ld.mapfile: false
$

I think we should have a very clear delineation of what goes in a 
pkg.yml file, and what goes in other, individual yml files. Compilers 
and targets should be broken into their own yml files, with their own 
definitions, and the pkg.yml should be uniform, without target & 
compiler specific details.

What do others think?  If people are +1 on this, let's get this changed 
prior to release.

Cheers,
Sterling