makedist script does not handle non-GNU systems correctly

[NattyNarwhal]

Description

While it does mandate GNU tar and checks for it correctly, it:

• Seems to use touch in a manner that confuses macOS touch. Oddly, the date it passes looks valid for the format, so I'm not sure why it complains.
• Does not check for the proper md5(sum) binary, assuming the GNU coreutils name of md5sum, when on macOS and BSD systems, it's md5.
  For example:

[...]
makedist: Resetting the modification and access times of package files to 2024-06-27T10:26:23-03:00
touch: out of range or illegal time specification: YYYY-MM-DDThh:mm:SS[.frac][tz]

makedist: Creating php-8.4.0alpha1test.tar archive.
makedist: Creating php-8.4.0alpha1test.tar.gz archive.
./scripts/dev/makedist: line 184: md5sum: command not found
makedist: Creating php-8.4.0alpha1test.tar.bz2 archive.
./scripts/dev/makedist: line 192: md5sum: command not found
makedist: Creating php-8.4.0alpha1test.tar.xz archive.
./scripts/dev/makedist: line 200: md5sum: command not found

makedist: Cleaning up.

makedist: All done.

PHP Version

PHP 8.4.0-dev

Operating System

macOS 14.5

[NattyNarwhal]

Same for gen_verify_stub

./scripts/dev/gen_verify_stub: line 44: sha256sum: command not found
./scripts/dev/gen_verify_stub: line 44: sha256sum: command not found
./scripts/dev/gen_verify_stub: line 44: sha256sum: command not found

[NattyNarwhal]

touch looks like it only can handle UTC dates:

An optional letter Z indicating the time is in UTC. Otherwise, the time is assumed to be in local time. Local time is affected by the value of the TZ environment variable.