diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0342181e9..d6d850a30 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -818,16 +818,14 @@ endif()
 if(APPLE)
     # generating a macOS icns file (see https://stackoverflow.com/a/20703594)
     add_custom_command(OUTPUT ${PROJECT_SOURCE_DIR}/res/augustus.icns
-        COMMAND mkdir -p augustus.iconset
-        COMMAND sips -z 16 16    augustus_256.png --out augustus.iconset/icon_16x16.png
-        COMMAND sips -z 32 32    augustus_256.png --out augustus.iconset/icon_16x16@2x.png
-        COMMAND sips -z 32 32    augustus_256.png --out augustus.iconset/icon_32x32.png
-        COMMAND sips -z 64 64    augustus_256.png --out augustus.iconset/icon_32x32@2x.png
-        COMMAND sips -z 128 128  augustus_256.png --out augustus.iconset/icon_128x128.png
-        COMMAND sips -z 256 256  augustus_256.png --out augustus.iconset/icon_128x128@2x.png
-        COMMAND sips -z 256 256  augustus_256.png --out augustus.iconset/icon_256x256.png
-        COMMAND sips -z 512 512  augustus_512.png --out augustus.iconset/icon_256x256@2x.png
-        COMMAND iconutil -c icns augustus.iconset
+        COMMAND mkdir augustus.iconset
+        COMMAND convert augustus_256.png -resize 16x16 augustus.iconset/icon_16.png
+        COMMAND convert augustus_256.png -resize 32x32 augustus.iconset/icon_32.png
+        COMMAND convert augustus_256.png -resize 64x64 augustus.iconset/icon_64.png
+        COMMAND convert augustus_256.png -resize 128x128 augustus.iconset/icon_128.png
+        COMMAND cp augustus_256.png augustus.iconset/icon_256.png
+        COMMAND cp augustus_512.png augustus.iconset/icon_512.png
+        COMMAND png2icns augustus.icns augustus.iconset/icon_{16,32,64,128,256,512}.png
         COMMAND rm -R augustus.iconset
         WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/res)
     set_source_files_properties(${PROJECT_SOURCE_DIR}/res/augustus.icns PROPERTIES
diff --git a/cmake/FindSDL2_mixer.cmake b/cmake/FindSDL2_mixer.cmake
index c3d0b84fe..3e9115dd5 100644
--- a/cmake/FindSDL2_mixer.cmake
+++ b/cmake/FindSDL2_mixer.cmake
@@ -75,7 +75,6 @@ ELSE()
         PATH_SUFFIXES include include/SDL2
         PATHS ${SDL2_SEARCH_PATHS}
       )
-      set(SDL2_MIXER_INCLUDE_DIR "${SDL2_MIXER_INCLUDE_DIR}/Headers")
     endif()
 
     if(NOT APPLE OR NOT EXISTS "${SDL2_MIXER_INCLUDE_DIR}/SDL_mixer.h")