Allow the platform itself to set on which platform we need to build the dep

For some complex build, we may want to build a dependency on another
platform that the target platform.

kiwixbuild/builder.py

@@ -76,10 +76,7 @@ class Builder:
 
         targetPlatform = PlatformInfo.get_platform(targetPlatformName)
         for dep in target.get_dependencies(targetPlatform, True):
-            if isinstance(dep, tuple):
-                depPlatform, depName = dep
-            else:
-                depPlatform, depName = targetPlatformName, dep
+            depPlatform, depName = targetPlatform.get_fully_qualified_dep(dep)
             if (depPlatform, depName) in targets:
                 yield from self.order_dependencies((depPlatform, depName), targets)
         yield ('source', targetName)

kiwixbuild/platforms/base.py

@@ -65,6 +65,13 @@ class PlatformInfo(metaclass=_MetaPlatform):
             depPlatform.add_targets(depName, targets)
         return [(self.name, targetName)]
 
+    def get_fully_qualified_dep(self, dep):
+         if isinstance(dep, tuple):
+            return dep
+         else:
+            return self.name, dep
+
+
     def get_cross_config(self):
         return {}