fixup: rename flag, remove if-else-chain

Co-authored-by: konsumlamm <[email protected]>

Author: Jeffrey Young

unordered-containers.cabal

@@ -77,15 +77,10 @@ library
     MagicHash,
     BangPatterns
 
-  if flag(noMsse42)
-    ghc-options: -Wall -O2 -fwarn-tabs -ferror-spans
-  else
+  ghc-options: -Wall -O2 -fwarn-tabs -ferror-spans
+  if !flag(noMsse42) && arch(x86_64)
     -- only enable flag on x86
-    if arch(i386) || arch(x86_64)
-      ghc-options: -Wall -O2 -fwarn-tabs -ferror-spans -msse4.2
-    else
-    -- else, get whatever GHC gives you
-    ghc-options: -Wall -O2 -fwarn-tabs -ferror-spans
+    ghc-options: -msse4.2
 
   -- For dumping the generated code:
   -- ghc-options: -ddump-simpl -ddump-stg-final -ddump-cmm -ddump-asm -ddump-to-file