Add command line argument parsing to the Windows packaging script.
As discussed here:
https://discourse.llvm.org/t/build-llvm-release-bat-script-options
Add a function to parse command line arguments: `parse_args`.
The format for the arguments is:
Boolean: --option
Value: --option<separator>value
with `<separator>` being: space, colon, semicolon or equal sign
Command line usage example:
my-batch-file.bat --build --type=release --version 123
It will create 3 variables:
`build` with the value `true`
`type` with the value `release`
`version` with the value `123`
Usage:
set "build="
set "type="
set "version="
REM Parse arguments.
call :parse_args %*
if defined build (
...
)
if %type%=='release' (
...
)
if %version%=='123' (
...
)