Follow error message changes

testsuite/tests/ghc-regress/module/mod42.stderr

 
 mod42.hs:3:0:
     Illegal instance declaration for `Eq a'
-	(All instance types must be of the form (T t1 ... tn)
-	 where T is not a synonym.
-	 Use -XTypeSynonymInstances if you want to disable this.)
+	(All instance types must be of the form (T a1 ... an)
+	 where a1 ... an are distinct type *variables*
+	 Use -XFlexibleInstances if you want to disable this.)
     In the instance declaration for `Eq a'

testsuite/tests/ghc-regress/parser/should_fail/read039.stderr

@@ -2,5 +2,5 @@
 read039.hs:7:0:
     Can't make a derived instance of `C Foo'
       (`C' is not a derivable class
-       Try -fglasgow-exts for GHC's newtype-deriving extension)
+       Try -XGeneralizedNewtypeDeriving for GHC's newtype-deriving extension)
     In the newtype declaration for `Foo'

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail117.hs

 module ShouldFail where
 
--- Without -fglasgow-exts both of these should fail
+-- Without any extensions enabled both of these should fail
 
 newtype N1 = N1 Int deriving ( Enum )
 data    N2 = N2 Int deriving ( Enum )

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail117.stderr

@@ -2,7 +2,7 @@
 tcfail117.hs:5:0:
     Can't make a derived instance of `Enum N1'
       (`N1' has non-nullary constructors
-       Try -fglasgow-exts for GHC's newtype-deriving extension)
+       Try -XGeneralizedNewtypeDeriving for GHC's newtype-deriving extension)
     In the newtype declaration for `N1'
 
 tcfail117.hs:6:0: