cmark-gfm: new port

[wyuenho]

Description

cmark-gfm is an extended version of the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. This repository adds GitHub Flavored Markdown extensions to the upstream implementation, as defined in the spec.

The rest of the README is preserved as-is from the upstream source. Note that the library and binaries produced by this fork are suffixed with -gfm in order to distinguish them from the upstream.

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 15.2
Xcode 16.2

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL in commit message?
• checked your Portfile with port lint?
• tried existing tests with sudo port test?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?
• checked that the Portfile's most important variants haven't been broken?