Port C API docs to Meson (#10936)

* Port C API docs to Meson

* don't cross-compile the docs

package.nix

@@ -20,7 +20,6 @@
 , git
 , gtest
 , jq
-, doxygen
 , libarchive
 , libcpuid
 , libgit2
@@ -53,8 +52,7 @@
 , versionSuffix ? ""
 , officialRelease ? false
 
-# Whether to build Nix. Useful to skip for tasks like (a) just
-# generating API docs or (b) testing existing pre-built versions of Nix
+# Whether to build Nix. Useful to skip for tasks like testing existing pre-built versions of Nix
 , doBuild ? true
 
 # Run the unit tests as part of the build. See `installUnitTests` for an
@@ -93,10 +91,6 @@
 # - readline
 , readlineFlavor ? if stdenv.hostPlatform.isWindows then "readline" else "editline"
 
-# Whether to build the external API docs, can be done separately from
-# everything else.
-, enableExternalAPIDocs ? forDevShell
-
 # Whether to install unit tests. This is useful when cross compiling
 # since we cannot run them natively during the build, but can do so
 # later.
@@ -184,13 +178,6 @@ in {
           ./scripts/local.mk
         ] ++ lib.optionals buildUnitTests [
           ./doc/manual
-        ] ++ lib.optionals enableExternalAPIDocs [
-          ./doc/external-api
-        ] ++ lib.optionals enableExternalAPIDocs [
-          # Source might not be compiled, but still must be available
-          # for Doxygen to gather comments.
-          (fileset.difference ./src ./src/perl)
-          ./tests/unit
         ] ++ lib.optionals buildUnitTests [
           ./tests/unit
         ] ++ lib.optionals doInstallCheck [
@@ -204,7 +191,7 @@ in {
     ++ lib.optional doBuild "dev"
     # If we are doing just build or just docs, the one thing will use
     # "out". We only need additional outputs if we are doing both.
-    ++ lib.optional (doBuild && (enableManual || enableExternalAPIDocs)) "doc"
+    ++ lib.optional (doBuild && enableManual) "doc"
     ++ lib.optional installUnitTests "check"
     ++ lib.optional doCheck "testresults"
     ;
@@ -228,7 +215,6 @@ in {
   ] ++ lib.optionals (doInstallCheck || enableManual) [
     jq # Also for custom mdBook preprocessor.
   ] ++ lib.optional stdenv.hostPlatform.isLinux util-linux
-    ++ lib.optional enableExternalAPIDocs doxygen
   ;
 
   buildInputs = lib.optionals doBuild [
@@ -291,7 +277,6 @@ in {
     (lib.enableFeature doBuild "build")
     (lib.enableFeature buildUnitTests "unit-tests")
     (lib.enableFeature doInstallCheck "functional-tests")
-    (lib.enableFeature enableExternalAPIDocs "external-api-docs")
     (lib.enableFeature enableManual "doc-gen")
     (lib.enableFeature enableGC "gc")
     (lib.enableFeature enableMarkdown "markdown")
@@ -319,8 +304,7 @@ in {
     mkdir $testresults
   '';
 
-  installTargets = lib.optional doBuild "install"
-    ++ lib.optional enableExternalAPIDocs "external-api-html";
+  installTargets = lib.optional doBuild "install";
 
   installFlags = "sysconfdir=$(out)/etc";
 
@@ -344,9 +328,6 @@ in {
   ) + lib.optionalString enableManual ''
     mkdir -p ''${!outputDoc}/nix-support
     echo "doc manual ''${!outputDoc}/share/doc/nix/manual" >> ''${!outputDoc}/nix-support/hydra-build-products
-  '' + lib.optionalString enableExternalAPIDocs ''
-    mkdir -p ''${!outputDoc}/nix-support
-    echo "doc external-api-docs $out/share/doc/nix/external-api/html" >> ''${!outputDoc}/nix-support/hydra-build-products
   '';
 
   # So the check output gets links for DLLs in the out output.