Make clang 10 compile

[Trioct]

Summary

SUMMARY: None

Purpose of change

I like when game compile

Describe the solution

Listen 2 compiler

Describe alternatives you've considered

Nuh-uh

Testing

Compiles

Additional context

I have literally no idea why the compiler wants this but it makes the code go
If someone has a deeper understanding of the clang voodoo please tell me (like you don't want const tripoint???)

src/magic_spell_effect.cpp:795:42: error: loop variable 'pair' has type 'const std::pair<int, tripoint> &' but is initialized with type 'std::pair<const int, tripoint>' resulting in a copy [-Werror,-Wrange-loop-construct]
    for( const std::pair<int, tripoint> &pair : targets_ordered_by_range ) {
                                         ^

src/magic_spell_effect.cpp:795:10: note: use non-reference type 'std::pair<int, tripoint>' to keep the copy or type 'const std::pair<const int, tripoint> &' to prevent copying
    for( const std::pair<int, tripoint> &pair : targets_ordered_by_range ) {
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Trioct]

I didn't request that review, but I hope you can handle this gargantuan workload
Edit: oh I see, there's a code owners file, cool

[Qrox]

I have literally no idea why the compiler wants this but it makes the code go
If someone has a deeper understanding of the clang voodoo please tell me (like you don't want const tripoint???)

It's not voodoo, it's just because you're not supposed to modify the keys of a map, so when iterating through the elements of the map via std::pair, the key type has to be const, otherwise a copy is performed (like what the compiler says). What confuses me though is why GCC isn't warning about this.

[Trioct]

Oh sure, didn't see it was iterating through a map and so returning a key and a value. I assumed it was a vector of pairs or something, makes much more sense.