remove undefined option
set replace versions for rake and rspec

+ enabled rpm-build-ruby gem autodetection
! spec

disabled bootstrap

fixed miniruby bootstrap mode
LTO disabled (ruby built using LTO is broken)
enabled bootstrap to fix broken 2.7.4-alt1 build

^ 2.7.3 -> 2.7.4
! build of LTE errors

^ ruby 2.7.2 -> 2.7.3

get a patch from upstream to fix a bug when building with Bision 3.7.5

- by dropping dep to libgit, and build req to rpm-build-ruby replaced with

^ ruby 2.7.1 -> 2.7.2

! ruby development deps

fixed packaging on so-called armh

^ ruby 2.7.0 -> 2.7.1

^ ruby 2.5.5 -> 2.7.0
^ rubygems 3.0.1 -> 3.1.2
+ packaged gems gem-bundle-embedded, gem-racc-embedded

Disable valgrind for architectures which does not support it.

! spec according to changelog rules

+ ruby-mspec package
! spec: syntax, gem dependencies