duplicate big-go version tags functionality [ fix #4391 ]

[archie2x]

[ see #4391 for motivation ] This attempts to duplicate big-Go go1.X build tags in tinygo with a series of build tags in the form tinygo0.1,tinygo0.2,...

Also adds a '-full' command-line flag to see all of the tags.

% ./build/tinygo info -json -full
{
  "goarch": "arm64",
  "goarm": "6",
  [...]
  "build_tags": [
    "darwin",
    "arm64",
    "tinygo",
    "purego",
    "math_big_pure_go",
    "gc.precise",
    "scheduler.tasks",
    "serial.none",
    "tinygo0.1",       <---
    "tinygo0.2",       <---
    [...]
    "tinygo0.32",      <---
    "tinygo0.33"       <---
  ],
  "garbage_collector": "precise",
  "scheduler": "tasks",
  "llvm_triple": "arm64-apple-macosx11.0.0"
}

TODO:

• tests
• Version specification is constantly confusing. I'd be inclined to create a separate package for clarity s.t. the constants were of the formtinygoVersion.Major etc. instead of goenv.VersionMajor etc.
• define tinygo-dev build tag if "-dev" ?

  
  package tinygoVersion

const Major = 0 const Minor = 33 const Patch = 0 const Dev = "-dev" // "" for release

[aykevl]

I'm not entirely convinced we should be doing this. Can you explain why this is needed (and why you can't just use the latest tinygo for example)?

[archie2x]

I'm not entirely convinced we should be doing this. Can you explain why this is needed (and why you can't just use the latest tinygo for example)?

Thanks! Sorry: it was an early-morning PR. See Issue #4391 where I tried to illustrate the motivation.

[archie2x]

As mentioned in #4391, I agree this doesn't make sense for now.