Hi,
I maintain the eggdrop package in MacPorts. I just updated the port to fix some breakage caused by the 'inline' keyword, which is handled differently by clang as compared to GCC.
For MacPorts, I'm simply removing the three instances of this keyword, secure in the knowledge that clang will inline the code if it would help to do so.
You may wish to special-case the 'inline' keyword to be native compatible with clang (e.g. 'static inline'), or simply remove 'inline' entirely.
Here's a reference to the MacPorts thread on this topic:
https://trac.macports.org/ticket/44286
Cheers,
-dre