Offline install of Opam

Offline install that places opam in the installation directory.

Depending on the end-user's integer size, as reported by Sys.int_size, either 32-bit or 64-bit opam will be installed.

On macOS the end-user target ABI can be either darwin_arm64 or darwin_x86_64 when you have both dkml-base-compiler and conf-dkml-cross-toolchain installed in your switch, regardless whether your host's ABI is darwin_arm64 or darwin_x86.64. Otherwise on macOS the target ABI must match the host ABI.

The package version, and what [opam --version] returns, are closely associated with the Opam version from the Opam source code. The only modifications are to ensure that the package version can be ordered using semver. In particular:

• 2.2.0~alpha~dev -> 2.2.0~alpha0~20221231
• 2.2.0~alpha~1 -> 2.2.0~alpha1~20230601
• 2.2.0 -> 2.2.0

The dates (YYYYMMDD) are the Git commit dates in the Opam source code, and simply replacing the tildes (~) with dashes (-) is sufficient to be a semver version.