ruby: clean up dead code for removed versions

pkgs/development/interpreters/ruby/default.nix

@@ -57,7 +57,6 @@ let
     }:
     let
       ver = version;
-      atLeast31 = lib.versionAtLeast ver.majMin "3.1";
       atLeast32 = lib.versionAtLeast ver.majMin "3.2";
       # https://github.com/ruby/ruby/blob/v3_2_2/yjit.h#L21
       yjitSupported =
@@ -189,18 +188,10 @@ let
           enableParallelInstalling = false;
 
           patches =
-            op (lib.versionOlder ver.majMin "3.1") ./do-not-regenerate-revision.h.patch
+            op useBaseRuby (
-            ++ op 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 {
-                url = "https://github.com/ruby/ruby/commit/0acc05caf7518cd0d63ab02bfa036455add02346.patch";
-                hash = "sha256-43hI9L6bXfeujgmgKFVmiWhg7OXvshPCCtQ4TxqK1zk=";
-              })
-            ]
-            ++ 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

pkgs/development/interpreters/ruby/do-not-regenerate-revision.h.patch

@@ -1,23 +0,0 @@
-Do not regenerate revision.h
-
-Ruby's makefile compares the shipped version with the git revision to regenerate
-revision.h [1], but since we don't include git in buildInputs, this comparison
-fails and it can't find $(REVISION_H).
-
-[1] https://github.com/ruby/ruby/commit/97a5af62a318fcd93a4e5e4428d576c0280ddbae
-
-diff -Naur ruby.old/defs/gmake.mk ruby.new/defs/gmake.mk
---- ruby.old/defs/gmake.mk
-+++ ruby.new/defs/gmake.mk
-@@ -325,11 +325,9 @@
- 
- REVISION_IN_HEADER := $(shell sed -n 's/^\#define RUBY_FULL_REVISION "\(.*\)"/\1/p' $(srcdir)/revision.h 2>/dev/null)
- REVISION_LATEST := $(shell $(CHDIR) $(srcdir) && git log -1 --format=%H 2>/dev/null)
--ifneq ($(REVISION_IN_HEADER),$(REVISION_LATEST))
- # GNU make treat the target as unmodified when its dependents get
- # updated but it is not updated, while others may not.
- $(srcdir)/revision.h: $(REVISION_H)
--endif
- 
- # Query on the generated rdoc
- #