Fix Darwin / macOS make error / dynamic module loading

[michaelortmann]

Found by: barracuda156 Patch by: michaelortmann Fixes: #1662

One-line summary: Use the usual dlopen method, if darwin version >= 9 with native dlopen

Additional description (if needed): run misc/runautotools when merging (and misc/runautotools -f when testing this PR)

Also for darwin >= 9 switched default built type from static to dynamic and dropped the WEIRD_OS mark Also removed dead old code: https://github.com/eggheads/eggdrop/blob/028e756076537d7199e152fec29f70db669f67ae/aclocal.m4#L628-L630 rld was overwritten with dyld all the time also rld is kinda pre posix 2001

Test cases demonstrating functionality (if applicable): I tested on Darwin michaels-iMac-Pro.local 22.6.0 Darwin Kernel Version 22.6.0: Thu Dec 5 23:45:11 PST 2024; root:xnu-8796.141.3.709.7~4/RELEASE_X86_64 x86_64 which is macOS Ventura 13.7.3 make eggdrop to test dynamic loading of modules successfully.