haskellPackages: xhtml is not bundled if haddock is disabled

The xhtml library is only built as part of the GHC build process if GHC
is disabled. This means that no GHC cross compiler has xhtml bundled,
since haddock can't be built if GHC is a cross compiler (see relevant
notes in the GHC nix expressions). This means that all packages
depending on xhtml would currently fail to build when cross-compiled, as
haskellPackages would assume it'd be provided by GHC. This is fixed by
this commit.

pkgsStatic hits this case, so we test compilation of xhtml for these
package sets which will remind us to update the attribute name whenever
its version changes.

pkgs/development/haskell-modules/configuration-ghc-8.10.x.nix

@@ -43,7 +43,9 @@ self: super: {
   time = null;
   transformers = null;
   unix = null;
-  xhtml = null;
+  # GHC only bundles the xhtml library if haddock is enabled, check if this is
+  # still the case when updating: https://gitlab.haskell.org/ghc/ghc/-/blob/0198841877f6f04269d6050892b98b5c3807ce4c/ghc.mk#L463
+  xhtml = if self.ghc.hasHaddock or true then null else self.xhtml_3000_2_2_1;
 
   # cabal-install needs more recent versions of Cabal and base16-bytestring.
   cabal-install = super.cabal-install.overrideScope (self: super: {

pkgs/development/haskell-modules/configuration-ghc-8.6.x.nix

@@ -42,7 +42,9 @@ self: super: {
   time = null;
   transformers = null;
   unix = null;
-  xhtml = null;
+  # GHC only bundles the xhtml library if haddock is enabled, check if this is
+  # still the case when updating: https://gitlab.haskell.org/ghc/ghc/-/blob/0198841877f6f04269d6050892b98b5c3807ce4c/ghc.mk#L463
+  xhtml = if self.ghc.hasHaddock or true then null else self.xhtml_3000_2_2_1;
 
   # Needs Cabal 3.0.x.
   cabal-install = super.cabal-install.overrideScope (self: super: { Cabal = self.Cabal_3_2_1_0; });

pkgs/development/haskell-modules/configuration-ghc-8.8.x.nix

@@ -42,7 +42,9 @@ self: super: {
   time = null;
   transformers = null;
   unix = null;
-  xhtml = null;
+  # GHC only bundles the xhtml library if haddock is enabled, check if this is
+  # still the case when updating: https://gitlab.haskell.org/ghc/ghc/-/blob/0198841877f6f04269d6050892b98b5c3807ce4c/ghc.mk#L463
+  xhtml = if self.ghc.hasHaddock or true then null else self.xhtml_3000_2_2_1;
 
   # GHC 8.8.x can build haddock version 2.23.*
   haddock = self.haddock_2_23_1;

pkgs/development/haskell-modules/configuration-ghc-9.0.x.nix

@@ -44,7 +44,9 @@ self: super: {
   time = null;
   transformers = null;
   unix = null;
-  xhtml = null;
+  # GHC only bundles the xhtml library if haddock is enabled, check if this is
+  # still the case when updating: https://gitlab.haskell.org/ghc/ghc/-/blob/0198841877f6f04269d6050892b98b5c3807ce4c/ghc.mk#L463
+  xhtml = if self.ghc.hasHaddock or true then null else self.xhtml_3000_2_2_1;
 
   # cabal-install needs more recent versions of Cabal and base16-bytestring.
   cabal-install = (doJailbreak super.cabal-install).overrideScope (self: super: {

pkgs/development/haskell-modules/configuration-ghc-9.2.x.nix

@@ -44,7 +44,9 @@ self: super: {
   time = null;
   transformers = null;
   unix = null;
-  xhtml = null;
+  # GHC only bundles the xhtml library if haddock is enabled, check if this is
+  # still the case when updating: https://gitlab.haskell.org/ghc/ghc/-/blob/0198841877f6f04269d6050892b98b5c3807ce4c/ghc.mk#L463
+  xhtml = if self.ghc.hasHaddock or true then null else self.xhtml_3000_2_2_1;
 
   # Tests fail because of typechecking changes
   conduit = dontCheck super.conduit;

pkgs/development/haskell-modules/configuration-ghc-head.nix

@@ -52,7 +52,9 @@ self: super: {
   time = null;
   transformers = null;
   unix = null;
-  xhtml = null;
+  # GHC only bundles the xhtml library if haddock is enabled, check if this is
+  # still the case when updating: https://gitlab.haskell.org/ghc/ghc/-/blob/0198841877f6f04269d6050892b98b5c3807ce4c/ghc.mk#L463
+  xhtml = if self.ghc.hasHaddock or true then null else self.xhtml_3000_2_2_1;
 
   # https://github.com/tibbe/unordered-containers/issues/214
   unordered-containers = dontCheck super.unordered-containers;

pkgs/top-level/release-haskell.nix

@@ -317,6 +317,7 @@ let
                 random
                 QuickCheck
                 cabal2nix
+                xhtml # isn't bundled for cross
               ;
             };
 
@@ -327,6 +328,7 @@ let
                 random
                 QuickCheck
                 cabal2nix
+                xhtml # isn't bundled for cross
               ;
             };
           };