Log Message:
sysutils/fastfetch: enable pkgsrc package count on Linux/macOS

Tested on Slackware 15.0. Not tested on macOS.
SunOS already builds pkgsrc support by default (tested: OmniOS).

Also fix bug (ours) whereby setting TARGET_DIR_ETC to PKG_SYSCONFDIR
prevents fastfetch from opening /etc/os-release and/or /etc/lsb-release
on Linux.

Bump revision.