Use const pointers in secure_channel_tls_handler.c.

[teo-tsirpanis]

Issue #, if available:

Description of changes:

This PR uses PCCERT_*** types in two cases, which are aliases for const pointers.

Fixes build failures on MinGW.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[waahm7]

Unfortunately, at the moment we don't support MinGW. What is your use-case? Is this the only problem you are facing with MinGW, or is this just the first of N problems?

[teo-tsirpanis]

I discovered this while working updating dependencies (TileDB-Inc/TileDB#5010), and after applying this patch aws-c-io builds in MinGW¹. Before making the patch, I tried to build without this warning and without any warnings, but for some reason this warning could not be suppressed and always escalated to an error.

I think this change is good regardless of the MinGW situation, because it matches the constness of the pointers with the API signatures (example 1, example 2).

Footnotes

1. There was another error in aws-sdk-cpp which needs more thought on if and how to fix upstream. ↩

[waahm7]

Thanks, LGTM!

[waahm7]

Released in https://github.com/awslabs/aws-c-io/releases/tag/v0.14.16.