Fix warnings from GCC9

[LordAro]

Noisest one is https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wdeprecated-copy

Mostly fixed by removing explicit copy constructors in favour of implicit compiler, or removing the need for one (switching an array out with std::array)

Closes #7748
Closes #7751

[LordAro]

clang build now relies on OpenTTD/CompileFarm#37

[nikolas]

👍 looks good on my gcc 9.2.1 on Debian.

[glx22]

I really don't see how to fix

/home/vsts/work/1/s/src/script/api/script_goal.cpp:141:36: warning: comparison of constant 65536 with expression of type 'ScriptClient::ClientID' is always true [-Wtautological-constant-out-of-range-compare]
        EnforcePrecondition(false, client < (1 << 16));
                                   ~~~~~~ ^ ~~~~~~~~~
/home/vsts/work/1/s/src/script/api/script_error.hpp:24:8: note: expanded from macro 'EnforcePrecondition'
        if (!(condition)) {                                           \
              ^~~~~~~~~

[glx22]

doesn't work :(

[glx22]

doesn't work :(

[LordAro]

I'd suggest that it does actually work, but the warning is invalid. Newer versions of clang (8, at least) don't display this warning. Would need to check the generated code to be sure, but none of our official binaries built using clang, and gcc doesn't use these "short" enums by default