Fixes #7750.

Motivation / Problem

You could wire INT32_MAX+1 to another player, which resulted in -1, which is clamped to 0. The expectation of course is to wire the upper-bound, 20,000,000.

Description

Based on patch by JGR. Basically, use strtoull to parse string to int, instead of atoi.

Now no matter what you input, it is converted to an unsigned long, and casted into Money, meaning it will max-out (instead of bottom-out). Which is much more in line with what a player would expect.

Limitations

• You can still wire 0 to another player. This was already the case, and this still is the case after this PR.

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • PR must be added to API tracker