diff --git a/plugins/zynaddsubfx/fltk/CMakeLists.txt b/plugins/zynaddsubfx/fltk/CMakeLists.txt
index 648e43323..e7231f6d9 100644
--- a/plugins/zynaddsubfx/fltk/CMakeLists.txt
+++ b/plugins/zynaddsubfx/fltk/CMakeLists.txt
@@ -44,7 +44,7 @@ set(LIBRARY_OUTPUT_PATH ${FLTK_BINARY_DIR}/lib)
 set(ARCHIVE_OUTPUT_PATH ${FLTK_BINARY_DIR}/lib)
 
 # Search for modules in the FLTK source dir first
-set(CMAKE_MODULE_PATH "${FLTK_SOURCE_DIR}/CMake")
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${FLTK_SOURCE_DIR}/CMake)
 
 include_directories(${FLTK_SOURCE_DIR} ${FLTK_BINARY_DIR})
 
@@ -469,7 +469,6 @@ if(OPTION_USE_SYSTEM_LIBJPEG AND JPEG_FOUND)
    include_directories(${JPEG_INCLUDE_DIR})
    set(FLTK_BUILTIN_JPEG_FOUND FALSE)
 else()
-   add_subdirectory(jpeg)
    set(FLTK_JPEG_LIBRARIES fltk_jpeg)
    include_directories(${FLTK_SOURCE_DIR}/jpeg)
    set(FLTK_BUILTIN_JPEG_FOUND TRUE)
@@ -493,7 +492,6 @@ if(OPTION_USE_SYSTEM_ZLIB AND ZLIB_FOUND)
    include_directories(${ZLIB_INCLUDE_DIRS})
    set(FLTK_BUILTIN_ZLIB_FOUND FALSE)
 else()
-   add_subdirectory(zlib)
    set(FLTK_ZLIB_LIBRARIES fltk_z)
    set(ZLIB_INCLUDE_DIR ${FLTK_SOURCE_DIR}/zlib)
    include_directories(${FLTK_SOURCE_DIR}/zlib)
@@ -519,7 +517,6 @@ if(OPTION_USE_SYSTEM_LIBPNG AND PNG_FOUND)
    add_definitions(${PNG_DEFINITIONS})
    set(FLTK_BUILTIN_PNG_FOUND FALSE)
 else()
-   add_subdirectory(png)
    set(FLTK_PNG_LIBRARIES fltk_png)
    set(HAVE_PNG_H 1)
    set(HAVE_PNG_GET_VALID 1)
@@ -590,7 +587,6 @@ if(CMAKE_CROSSCOMPILING)
       PROPERTIES IMPORTED_LOCATION ${FLUID_PATH}
       )
 else()
-#   add_subdirectory(fluid)
    set(FLTK_FLUID_EXECUTABLE fluid)
    set(FLTK_FLUID_PATH ${EXECUTABLE_OUTPUT_PATH}/${FLTK_FLUID_EXECUTABLE})
 endif(CMAKE_CROSSCOMPILING)