Ruby 2.4 Removal

Per our standard Ruby support policy, I am planning to remove Ruby 2.4
from the ports tree at p2k19, as it will be completely unsupported
before the release of OpenBSD 6.7. Nothing currently depends on it, so
this should cause no problems.

Here's the diff for ruby.port.mk. I also have diffs prepared for
ruby-module.5 and quirks.

Thanks,
Jeremy

Index: ruby.port.mk
===================================================================
RCS file: /cvs/ports/lang/ruby/ruby.port.mk,v
retrieving revision 1.97
diff -u -p -r1.97 ruby.port.mk
--- ruby.port.mk 29 Apr 2019 00:35:58 -0000 1.97
+++ ruby.port.mk 2 Nov 2019 17:28:07 -0000
@@ -24,7 +24,7 @@ MODRUBY_HANDLE_FLAVORS ?= No
# If ruby.pork.mk should handle FLAVORs, define a separate FLAVOR
# for each ruby interpreter
. if !defined(FLAVORS)
-FLAVORS= ruby24 ruby25 ruby26
+FLAVORS= ruby25 ruby26
. if !${CONFIGURE_STYLE:L:Mext}
FLAVORS+= jruby
. endif
@@ -52,11 +52,10 @@ FLAVOR = ruby26

# Check for conflicting FLAVORs and set MODRUBY_REV appropriately based
# on the FLAVOR.
-. for i in ruby24 ruby25 ruby26 jruby
+. for i in ruby25 ruby26 jruby
. if ${FLAVOR:M$i}
MODRUBY_REV = ${i:C/ruby([0-9])/\1./}
-. if ${FLAVOR:N$i:Mruby24} || \
- ${FLAVOR:N$i:Mruby25} || \
+. if ${FLAVOR:N$i:Mruby25} || \
${FLAVOR:N$i:Mruby26} || \
${FLAVOR:N$i:Mjruby}
ERRORS += "Fatal: Conflicting flavors used: ${FLAVOR}"