haskell.compiler: also build manual for cross-compilers

The reasoning given for disabling it is flawed: In most cases, sphinx
and its dependencies are already in the binary cache, since we only need
them as build tools—sphinx for the build platform is just the normal
pkgs.sphinx, since it doesn't care about targetPlatform.

We just need to disable it when the buildPlatform is also musl, so we
avoid pulling in sphinx in pkgsMusl.

pkgs/development/compilers/ghc/8.10.7.nix

@@ -44,12 +44,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.0.2.nix

@@ -46,12 +46,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pullls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.2.4.nix

@@ -46,12 +46,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.2.5.nix

@@ -46,12 +46,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.2.6.nix

@@ -46,12 +46,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.2.7.nix

@@ -46,12 +46,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.2.8.nix

@@ -46,12 +46,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.2.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.3.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.4.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.5.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.6.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.7.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/9.4.8.nix

@@ -48,12 +48,9 @@
 
 , #  Whether to build sphinx documentation.
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , enableHaddockProgram ?

pkgs/development/compilers/ghc/common-hadrian.nix

@@ -162,13 +162,11 @@
   }
 
 , #  Whether to build sphinx documentation.
+  # TODO(@sternenseemann): Hadrian ignores the --docs flag if finalStage = Stage1
   enableDocs ? (
-    # Docs disabled for musl and cross because it's a large task to keep
-    # all `sphinx` dependencies building in those environments.
-    # `sphinx` pulls in among others:
-    # Ruby, Python, Perl, Rust, OpenGL, Xorg, gtk, LLVM.
-    (stdenv.targetPlatform == stdenv.hostPlatform)
-    && !stdenv.hostPlatform.isMusl
+    # Docs disabled if we are building on musl because it's a large task to keep
+    # all `sphinx` dependencies building in this environment.
+    !stdenv.buildPlatform.isMusl
   )
 
 , # Whether to disable the large address space allocator