Backport "suppress warning: 'const' attribute on function returning 'void' "
include/ruby/ruby.h are used for extension builds, and when a recent gcc is called with -Wall, the build fails. This can cause failures with mkmf for instance in pkg_config() lookup.
The resolving commit to ruby-2.5 was: https://github.com/ruby/ruby/commit/027b576b31cd12bad575b3a39476726273f58c41
Can this commit please be backported to older ruby versions?
This patch is also used for RubyInstaller-2.4.