diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1e1817f542..80aa7ff083 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -95,6 +95,11 @@ if (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUXX)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fext-numeric-literals" )
 endif()
 
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+    # On GCC and Clang, no return from a non-void function is a warning only. Here, we make it an error.
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=return-type" )
+endif()
+
 # Where all the bundled libraries reside?
 set(LIBDIR ${CMAKE_CURRENT_SOURCE_DIR}/src/)
 # For the bundled boost libraries (boost::nowide)
diff --git a/src/libslic3r/Format/3mf.cpp b/src/libslic3r/Format/3mf.cpp
index 43c99f19fd..c9b4989f56 100644
--- a/src/libslic3r/Format/3mf.cpp
+++ b/src/libslic3r/Format/3mf.cpp
@@ -667,7 +667,8 @@ namespace Slic3r {
                 add_error("Error while reading config data to buffer");
                 return;
             }
-            bundle.load_config_string(buffer.data(), archive_filename.c_str());
+//FIXME Get rid of the dependencies on slic3r GUI library!
+//            bundle.load_config_string(buffer.data(), archive_filename.c_str());
         }
     }
 
diff --git a/src/libslic3r/Format/AMF.cpp b/src/libslic3r/Format/AMF.cpp
index 458ce79de7..89a0eacbe6 100644
--- a/src/libslic3r/Format/AMF.cpp
+++ b/src/libslic3r/Format/AMF.cpp
@@ -467,7 +467,8 @@ void AMFParserContext::endElement(const char * /* name */)
 
     case NODE_TYPE_METADATA:
         if ((m_preset_bundle != nullptr) && strncmp(m_value[0].c_str(), SLIC3R_CONFIG_TYPE, strlen(SLIC3R_CONFIG_TYPE)) == 0) {
-            m_preset_bundle->load_config_string(m_value[1].c_str(), m_archive_filename.c_str());
+//FIXME Get rid of the dependencies on slic3r GUI library!
+//            m_preset_bundle->load_config_string(m_value[1].c_str(), m_archive_filename.c_str());
         }
         else if (strncmp(m_value[0].c_str(), "slic3r.", 7) == 0) {
             const char *opt_key = m_value[0].c_str() + 7;
diff --git a/src/slic3r/GUI/GLToolbar.hpp b/src/slic3r/GUI/GLToolbar.hpp
index 65d6748ffe..c67e78f58c 100644
--- a/src/slic3r/GUI/GLToolbar.hpp
+++ b/src/slic3r/GUI/GLToolbar.hpp
@@ -2,7 +2,7 @@
 #define slic3r_GLToolbar_hpp_
 
 #include "../../slic3r/GUI/GLTexture.hpp"
-#include "../../callback.hpp"
+#include "callback.hpp"
 
 #include <string>
 #include <vector>
diff --git a/src/slic3r/GUI/GUI.hpp b/src/slic3r/GUI/GUI.hpp
index 8dfaf42c66..9539cd7cc3 100644
--- a/src/slic3r/GUI/GUI.hpp
+++ b/src/slic3r/GUI/GUI.hpp
@@ -4,7 +4,7 @@
 #include <string>
 #include <vector>
 #include "PrintConfig.hpp"
-#include "../../callback.hpp"
+#include "callback.hpp"
 #include "GUI_ObjectParts.hpp"
 
 #include <wx/intl.h>