[Chapel Merge] Use the complex initializer that's supported by cl

Branch: refs/heads/main
Revision: 0085fba
Author: e-kayrakli
Link: Use the complex initializer that's supported by clang 11 by e-kayrakli · Pull Request #20320 · chapel-lang/chapel · GitHub
Log Message:

Merge pull request #20320 from e-kayrakli/complex-fix

Use the complex initializer that's supported by clang 11

clang-11 doesn't support __builtin_complex causing build failures, but it supports complex initializer lists. This PR uses those to create _Complex_I if it is not defined.

[Hopefully trivial, surely urgent, not reviewed]

Modified Files:
M runtime/include/chpltypes.h

Compare: https://github.com/chapel-lang/chapel/compare/7e6992d390ea...0085fba89a21