openkal-macos 0.9.1, openkal-windows 0.7.4

[Sunrisepeak]

Adds openkal-macos 0.9.1 and openkal-windows 0.7.4 on every platform.

• openkal-macos 0.9.1 (0.9.1 --- the second register comes back from every call openkal-macos#20): programs built with --release start; the system call wrapper now declares the second returned register, which an optimizing compiler relied on across a call.
• openkal-windows 0.7.4 (0.7.4 --- a named value is reported as it was set openkal-windows#23): environment values are reported as set; a forward-slashed ComSpec broke every command run through the command interpreter.

package	version	sha256 (GitHub archive = GitCode mirror)
openkal-macos	0.9.1	e65c58bcc226d3c3d33299e008e36a2a94f06e39317b9766a92de9680bea8adb
openkal-windows	0.7.4	8880b885df7426f201d1026d1d1c60d033e33c4cec3411cfae3ae9175b83f3d8

Each archive was downloaded twice from GitHub and once from the GitCode mirror; the hashes agree.