Resolve transitive package deps in fpc CI backend

TPackageGraph.BuildPackageAt built a package's -Fu search path from
its direct RequiredPkgs only. That is correct for the packages here,
but breaks once a package depends on another package whose units pull
in a third: the intermediate's transitive deps never reach -Fu.

Build the -Fu set from the transitive closure of dependency output
dirs instead, reusing the CollectUnitPaths walker the project build
path already relies on. Keeps the shared make.pas orchestrator
identical across repos.

Only the fpc backend is affected; the lazbuild backend resolves the
graph itself via --add-package-link + --recursive.

Author: Xor-el

.github/workflows/make.pas

@@ -1205,9 +1205,10 @@ procedure TPackageGraph.CollectUnitPaths(const AIndex: Integer;
 function TPackageGraph.BuildPackageAt(const AIndex: Integer): Boolean;
 var
   Pkg: TLpkPackage;
-  Args: TStringList;
-  BuildOutput, OutDir, DepPath: string;
-  J: Integer;
+  Args, DepPaths: TStringList;
+  Visited: specialize TList<Integer>;
+  BuildOutput, OutDir: string;
+  J, DepIdx: Integer;
 begin
   Result := True;
   Pkg := GetPackage(AIndex);
@@ -1225,12 +1226,25 @@ function TPackageGraph.BuildPackageAt(const AIndex: Integer): Boolean;
     for J := 0 to Pkg.SourceDirs.Count - 1 do
       TLazXml.AppendFuIfMissing(Pkg.SourceDirs[J], Args);
     TLazXml.AppendFuIfMissing(Pkg.PkgDir, Args);
-    for J := 0 to Pkg.RequiredNames.Count - 1 do
-    begin
-      if IsBuiltinPackage(Pkg.RequiredNames[J]) then
-        Continue;
-      DepPath := UnitPathFor(Pkg.RequiredNames[J]);
-      TLazXml.AppendFuIfMissing(DepPath, Args);
+    // A required package's units reference their own dependencies' units, so
+    // the compile needs the transitive closure of dependency output dirs on
+    // -Fu, not just the direct requires (mirrors how projects resolve paths).
+    DepPaths := TStringList.Create;
+    Visited := specialize TList<Integer>.Create;
+    try
+      for J := 0 to Pkg.RequiredNames.Count - 1 do
+      begin
+        if IsBuiltinPackage(Pkg.RequiredNames[J]) then
+          Continue;
+        DepIdx := FindIndexByName(Pkg.RequiredNames[J]);
+        if DepIdx >= 0 then
+          CollectUnitPaths(DepIdx, Visited, DepPaths);
+      end;
+      for J := 0 to DepPaths.Count - 1 do
+        TLazXml.AppendFuIfMissing(DepPaths[J], Args);
+    finally
+      Visited.Free;
+      DepPaths.Free;
     end;
     TLazXml.AppendPackageBuildArgs(Args, ExtractFileName(Pkg.StubPas), OutDir);