ngIRCd: Set "sysconfdir" to #{HOMEBREW_PREFIX}/etc/ngircd

This prevents Homebrew from linking the configuration files into
the "sysconfdir" which would break updates when the user modified
the configuration file(s) ...

Signed-off-by: Alexander Barton <alex@barton.de>
ngircd: update 21.1 bottle.

Closes #27869.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
clasp 3.0.1
clasp: add 3.0.1 bottle.

Closes #27871.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
freetype: explicity disable harfbuzz

Harfbuzz depends on freetype. Homebrew can't and probably never will
handle circular dependencies such as this.
avidemux: use install_symlink
clozure-cl: modernize formula