ruby: fix cross compilation

pkgs/development/interpreters/ruby/default.nix

@@ -21,6 +21,7 @@ let
   generic = { version, sha256, cargoSha256 ? null }: let
     ver = version;
     atLeast30 = lib.versionAtLeast ver.majMin "3.0";
+    atLeast31 = lib.versionAtLeast ver.majMin "3.1";
     atLeast32 = lib.versionAtLeast ver.majMin "3.2";
     self = lib.makeOverridable (
       { stdenv, buildPackages, lib
@@ -96,7 +97,10 @@ let
         enableParallelBuilding = true;
 
         patches = op (lib.versionOlder ver.majMin "3.1") ./do-not-regenerate-revision.h.patch
-          ++ op (atLeast30 && useBaseRuby) ./do-not-update-gems-baseruby.patch
+          ++ op (atLeast30 && useBaseRuby) (
+            if atLeast32 then ./do-not-update-gems-baseruby-3.2.patch
+            else ./do-not-update-gems-baseruby.patch
+          )
           ++ ops (ver.majMin == "3.0") [
             # Ruby 3.0 adds `-fdeclspec` to $CC instead of $CFLAGS. Fixed in later versions.
             (fetchpatch {
@@ -104,6 +108,14 @@ let
               sha256 = "sha256-43hI9L6bXfeujgmgKFVmiWhg7OXvshPCCtQ4TxqK1zk=";
             })
           ]
+          ++ ops (ver.majMin == "3.1") [
+            # Ruby 3.1.3 cannot find pkg-config in mkmf.rb
+            # https://bugs.ruby-lang.org/issues/19189
+            (fetchpatch {
+              url = "https://github.com/ruby/ruby/commit/613fca01486e47dee9364a2fd86b5f5e77fe23c8.patch";
+              sha256 = "sha256-0Ku7l6VEpcvxexL9QA5+mNER4v8gYZOJhAjhCL1WDpw=";
+            })
+          ]
           ++ ops (!atLeast30 && rubygemsSupport) [
             # We upgrade rubygems to a version that isn't compatible with the
             # ruby 2.7 installer. Backport the upstream fix.
@@ -118,6 +130,13 @@ let
               url = "https://github.com/ruby/ruby/commit/261d8dd20afd26feb05f00a560abd99227269c1c.patch";
               sha256 = "0wrii25cxcz2v8bgkrf7ibcanjlxwclzhayin578bf0qydxdm9qy";
             })
+          ]
+          ++ ops atLeast31 [
+            # When using a baseruby, ruby always sets "libdir" to the build
+            # directory, which nix rejects due to a reference in to /build/ in
+            # the final product. Removing this reference doesn't seem to break
+            # anything and fixes cross compliation.
+            ./dont-refer-to-build-dir.patch
           ];
 
         cargoRoot = opString yjitSupport "yjit";

pkgs/development/interpreters/ruby/do-not-update-gems-baseruby-3.2.patch

@@ -0,0 +1,13 @@
+diff --git a/common.mk b/common.mk
+index 3798f82bc6..4d07b28aa4 100644
+--- a/common.mk
++++ b/common.mk
+@@ -1374,7 +1374,7 @@ update-config_files: PHONY
+ 	    config.guess config.sub
+ 
+ refresh-gems: update-bundled_gems prepare-gems
+-prepare-gems: $(HAVE_BASERUBY:yes=update-gems) $(HAVE_BASERUBY:yes=extract-gems)
++prepare-gems:
+ extract-gems: $(HAVE_BASERUBY:yes=update-gems)
+ 
+ update-gems$(gnumake:yes=-sequential): PHONY

pkgs/development/interpreters/ruby/dont-refer-to-build-dir.patch

@@ -0,0 +1,12 @@
+diff --git a/tool/fake.rb b/tool/fake.rb
+index 91dfb041c4..9c235f1e3a 100644
+--- a/tool/fake.rb
++++ b/tool/fake.rb
+@@ -48,7 +48,6 @@ class File
+   $builtruby ||= File.join(builddir, config['RUBY_INSTALL_NAME'] + config['EXEEXT'])
+   RbConfig.fire_update!("builddir", builddir)
+   RbConfig.fire_update!("buildlibdir", builddir)
+-  RbConfig.fire_update!("libdir", builddir)
+   RbConfig.fire_update!("prefix", $topdir)
+   RbConfig.fire_update!("top_srcdir", $top_srcdir ||= top_srcdir)
+   RbConfig.fire_update!("extout", $extout)