Motivation / Problem

VS2017 fails to compile our current code with

  Error: ..\src\currency.cpp(69): error C2440: 'initializing': cannot convert from 'const char [3]' to 'char'
  ..\src\currency.cpp(69): note: There is no context in which this conversion is possible

While the error is weird (and probably incorrect as VS2019 has no issue with our code), I think implicit copy from const char[] (string literal) to char[] is not fully legit.

Description

I added a constructor to do the copy without implicit casting.
Of course that removed the default constructor, so I re-added it.
And with that VS2017 succeeds to build

Limitations

None I can think of.

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')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker