Add ability to join elements of std::initializer_list

[Rapotkinnik]

I agree that my contributions are licensed under the {fmt} license, and agree to future changes to the licensing.

[vitaut]

Thanks for the PR. Mostly looks good but please move this to fmt/ranges.h and apply clang-format to your changes.

[Rapotkinnik]

Sorry, but is it ok...

$ ./bin/Debug/ranges-test.exe
[==========] Running 0 tests from 0 test cases.
[==========] 0 tests from 0 test cases ran. (0 ms total)
[  PASSED  ] 0 tests.

...or I ran a wrong test?

[vitaut]

ranges-test require C++14:

fmt/test/ranges-test.cc

Line 17 in 85050aa

#if (__cplusplus > 201402L) || \

. You could move the JoinInitializerList test outside of the ifdef block but that's not critical.

[Rapotkinnik]

201402L

I built library this way cmake . -DCMAKE_CXX_STANDARD=14 and nothing changed...what was I doing wrong?=)

[vitaut]

My bad, it's > not >= in __cplusplus > 201402L, so it requires C++17.

[Rapotkinnik]

But when I did cmake . -DCMAKE_CXX_STANDARD=17
I got E:\Workspace\fmt\test\gtest\gtest.h(9692): error C2039: 'tr1': is not a member of 'std' [E:\Workspace\fmt\test\gmock.vc xproj]...

Is it a bug?

[vitaut]

Looks like a gtest bug.