Force older x86 platforms to recompile native gems

As described in
https://github.com/rake-compiler/rake-compiler-dock/issues/122, x86
precompiled native gems for a long time have used an image based on
CentOS 7, which uses glibc 2.17.

With https://github.com/rake-compiler/rake-compiler-dock/pull/126, the
image has been updated to Ubuntu 20.04, which uses glibc 2.29.

In `OhaiHelper#ruby_native_gems_unsupported?`, we previously forced a
number of older `aarch64` platforms to recompile the native gems
because `aarch64` has used Ubuntu 20.04 and hence glibc 2.29 for a
while.

With gems that use rake-compiler-dock v1.6.0 or higher (e.g. nokogiri,
prometheus-client-mmap, etc.), glibc 2.29 is now required even for
x86.

In prepration for these gem updates, ensure that all native Ruby gems
are recompiled to avoid quiet failures.

Relates to https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8865

Changelog: fixed

config/software/ruby.rb

@@ -90,6 +90,26 @@ env['CFLAGS'] << ' -O3 -g -pipe'
 # Workaround for https://bugs.ruby-lang.org/issues/19161
 env['CFLAGS'] << ' -std=gnu99' if OhaiHelper.get_centos_version.to_i == 7 || OhaiHelper.os_platform == 'sles'
+# We need to recompile native gems on SLES 12 and CentOS 7 because
+# precompiled gems such as nokogiri now require glibc >= 2.29,
+# and these operating systems use older versions.
+#
+# By default, Ruby C extensions use `RbConfig::MAKEFILE_CONFIG["CC"]`,
+# which is the C compiler used to build Ruby. Some C extensions can use
+# alternative compilers by defining the CC/CXX environment
+# variables. However, google-protobuf does not yet support this, but
+# https://github.com/protocolbuffers/protobuf/pull/19863 adds upstream
+# support. For now, compiling the Ruby interpreter with GCC 8 works and
+# avoids the need to specify the compiler for every extension that needs
+# it.
+if OhaiHelper.centos7?
+  env['CC'] = "/opt/rh/devtoolset-8/root/usr/bin/gcc"
+  env['CXX'] = "/opt/rh/devtoolset-8/root/usr/bin/g++"
+elsif OhaiHelper.sles12?
+  env['CC'] = "/usr/bin/gcc-8"
+  env['CXX'] = "/usr/bin/g++-8"
+end
+
 build do
   env['CFLAGS'] << ' -fno-omit-frame-pointer'
   # Fix for https://bugs.ruby-lang.org/issues/18409. This can be removed with Ruby 3.0+.

gitlab-ci-config/variables.yml

@@ -8,7 +8,7 @@ variables:
   # To be used for images that exist only on dev.gitlab.org
   DEV_BUILDER_IMAGE_REGISTRY: 'dev.gitlab.org:5005/cookbooks/gitlab-omnibus-builder'
   PUBLIC_BUILDER_IMAGE_REGISTRY: "registry.gitlab.com/gitlab-org/gitlab-omnibus-builder"
-  BUILDER_IMAGE_REVISION: "5.22.0"
+  BUILDER_IMAGE_REVISION: "5.23.0"
   # The registry to pull the assets image from
   ASSET_REGISTRY: "${CI_REGISTRY}"
   ASSET_SYNC_EXISTING_REMOTE_FILES: "keep"

lib/gitlab/ohai_helper.rb

@@ -198,16 +198,20 @@ class OhaiHelper
       os_platform == 'sles' && get_suse_version.to_i == 12
     end
-    # Currently rake-compiler-dock uses a Ubuntu 20.04 image to create the
-    # native gem for the aarch64-linux platform. As a result, anything
-    # using a glibc older than v2.29 will not work. We need to compile
-    # gems for these platforms.
+    # rake-compiler-dock v1.7.0 uses an Ubuntu 20.04 image to create
+    # precompiled native gems. As a result, precompiled gems will
+    # require glibc v2.29 or higher. On older platforms, we need to
+    # recompile these gems for them to work.
     def ruby_native_gems_unsupported?
       %w[
-        el-8_aarch64
+        amazon-2
         amazon-2_aarch64
         debian-buster_aarch64
+        el-7
+        el-8
+        el-8_aarch64
         raspbian-buster_aarch64
+        sles-12.5
       ].include?(platform_dir)
     end
   end