diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 14cd330c8..382cbfc23 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -26,6 +26,9 @@ find_package(
 	COMPONENTS OpenGL Xml Network
 	REQUIRED)
 find_package(OpenMP)
+if (NOT BUILD_MINI)
+	find_package(Qt5Qml)
+endif()
 
 message(STATUS "Searching for required components with bundled fallback")
 find_package(GLEW)
@@ -103,14 +106,24 @@ endif()
 
 ### Enter subdirectories
 
+# VCGLib -- required
+if(NOT VCGDIR)
+	get_filename_component(VCGDIR "${CMAKE_CURRENT_LIST_DIR}/vcglib" ABSOLUTE)
+	if(NOT EXISTS ${VCGDIR})
+		set(VCGDIR NOTFOUND)
+	endif()
+endif()
+set(VCGDIR "${VCGDIR}")
+
+if(NOT VCGDIR)
+	message(FATAL_ERROR "VCGLib not found. Please clone recursively the MeshLab repo.")
+endif()
+
+
 # External
 set(EXTERNAL_DIR ${CMAKE_CURRENT_SOURCE_DIR}/external)
-include(${CMAKE_CURRENT_SOURCE_DIR}/external_common.cmake)
-if(NOT BUILD_MINI)
-	message(STATUS "Searching for optional components")
-	find_package(Qt5Qml)
-	include(${EXTERNAL_DIR}/external.cmake)
-endif()
+include(${EXTERNAL_DIR}/external_common.cmake)
+add_subdirectory(${EXTERNAL_DIR})
 
 # Start automoc/autouic/autorcc
 set(CMAKE_AUTOMOC ON)
diff --git a/src/external/CMakeLists.txt b/src/external/CMakeLists.txt
new file mode 100644
index 000000000..fe3e0c10c
--- /dev/null
+++ b/src/external/CMakeLists.txt
@@ -0,0 +1,11 @@
+# Copyright 2019, 2020, Collabora, Ltd.
+# Copyright 2019, 2020, Visual Computing Lab, ISTI - Italian National Research Council
+# SPDX-License-Identifier: BSL-1.0
+
+# GLEW - required
+include(${EXTERNAL_DIR}/glew.cmake)
+
+if(NOT BUILD_MINI)
+	message(STATUS "Searching for optional components")
+	include(${EXTERNAL_DIR}/external.cmake)
+endif()
diff --git a/src/external_common.cmake b/src/external/external_common.cmake
similarity index 62%
rename from src/external_common.cmake
rename to src/external/external_common.cmake
index e5ed003ce..c5f22167b 100644
--- a/src/external_common.cmake
+++ b/src/external/external_common.cmake
@@ -12,23 +12,5 @@ if(BUILD_BUNDLED_SOURCES_WITHOUT_WARNINGS)
 	endif()
 endif()
 
-# GLEW - required
-include(${EXTERNAL_DIR}/glew.cmake)
-
-
-# VCGLib -- required
-if(NOT VCGDIR)
-	get_filename_component(VCGDIR "${CMAKE_CURRENT_LIST_DIR}/vcglib" ABSOLUTE)
-	if(NOT EXISTS ${VCGDIR})
-		set(VCGDIR NOTFOUND)
-	endif()
-endif()
-set(VCGDIR "${VCGDIR}")
-
-if(NOT VCGDIR)
-	message(FATAL_ERROR "VCGLib not found. Please clone recursively the MeshLab repo.")
-endif()
-
-
 # Eigen3 - required
 include(${EXTERNAL_DIR}/eigen.cmake)
diff --git a/src/meshlabplugins/io_u3d/CMakeLists.txt b/src/meshlabplugins/io_u3d/CMakeLists.txt
index 7f2c41cbe..e6091e150 100644
--- a/src/meshlabplugins/io_u3d/CMakeLists.txt
+++ b/src/meshlabplugins/io_u3d/CMakeLists.txt
@@ -8,7 +8,7 @@ if(TARGET external-IDTFConverter)
 	set(SOURCES io_u3d.cpp)
 
 	set(HEADERS io_u3d.h)
-	include_directories("${U3D_DIR}/src/IDTF")
+	include_directories("${EXTERNAL_DIR}/u3d/src/IDTF")
 
 	add_library(io_u3d MODULE ${SOURCES} ${HEADERS})
 
diff --git a/src/meshlabplugins/io_u3d/io_u3d.cpp b/src/meshlabplugins/io_u3d/io_u3d.cpp
index e35cdbde4..f6ddc35a0 100644
--- a/src/meshlabplugins/io_u3d/io_u3d.cpp
+++ b/src/meshlabplugins/io_u3d/io_u3d.cpp
@@ -81,7 +81,7 @@ bool U3DIOPlugin::save(
 		const int mask, 
 		const RichParameterList & par, 
 		vcg::CallBackPos *, 
-		QWidget *parent)
+		QWidget *)
 {
 	vcg::tri::Allocator<CMeshO>::CompactVertexVector(m.cm);
 	vcg::tri::Allocator<CMeshO>::CompactFaceVector(m.cm);