diff --git a/CMake/options.cmake b/CMake/options.cmake
index a4f781332..6957350b4 100644
--- a/CMake/options.cmake
+++ b/CMake/options.cmake
@@ -221,7 +221,6 @@ endif (UNIX)
 
 #######################################################################
 if (APPLE)
-  option (OPTION_APPLE_X11 "use X11" OFF)
   if (CMAKE_OSX_SYSROOT)
     list (APPEND FLTK_CFLAGS "-isysroot ${CMAKE_OSX_SYSROOT}")
   endif (CMAKE_OSX_SYSROOT)
@@ -229,7 +228,7 @@ endif (APPLE)
 
 # find X11 libraries and headers
 set (PATH_TO_XLIBS)
-if ((NOT APPLE OR OPTION_APPLE_X11) AND NOT WIN32)
+if (NOT APPLE AND NOT WIN32)
   include (FindX11)
   if (X11_FOUND)
     set (USE_X11 1)
@@ -239,22 +238,7 @@ if ((NOT APPLE OR OPTION_APPLE_X11) AND NOT WIN32)
     endif (X11_Xext_FOUND)
     get_filename_component (PATH_TO_XLIBS ${X11_X11_LIB} PATH)
   endif (X11_FOUND)
-endif ((NOT APPLE OR OPTION_APPLE_X11) AND NOT WIN32)
-
-if (OPTION_APPLE_X11)
-  if (NOT(${CMAKE_SYSTEM_VERSION} VERSION_LESS 17.0.0)) # a.k.a. macOS version ≥ 10.13
-    list (APPEND FLTK_CFLAGS "-D_LIBCPP_HAS_THREAD_API_PTHREAD")
-  endif (NOT(${CMAKE_SYSTEM_VERSION} VERSION_LESS 17.0.0))
-  include_directories (AFTER SYSTEM /opt/X11/include/freetype2)
-  if (PATH_TO_XLIBS)
-    set (LDFLAGS "-L${PATH_TO_XLIBS} ${LDFLAGS}")
-  endif (PATH_TO_XLIBS)
-  if (X11_INCLUDE_DIR)
-    set (TEMP_INCLUDE_DIR ${X11_INCLUDE_DIR})
-    list (TRANSFORM TEMP_INCLUDE_DIR PREPEND "-I")
-    list (APPEND FLTK_CFLAGS "${TEMP_INCLUDE_DIR}")
-  endif (X11_INCLUDE_DIR)
-endif (OPTION_APPLE_X11)
+endif (NOT APPLE AND NOT WIN32)
 
 #######################################################################
 option (OPTION_USE_POLL "use poll if available" OFF)
@@ -375,17 +359,10 @@ if (HAVE_GL)
 endif (HAVE_GL)
 
 if (OPTION_USE_GL)
-  if (OPTION_APPLE_X11)
-    set (OPENGL_FOUND TRUE)
-    set (OPENGL_LIBRARIES -L${PATH_TO_XLIBS} -lGLU -lGL)
-    unset(HAVE_GL_GLU_H CACHE)
-    find_file (HAVE_GL_GLU_H GL/glu.h PATHS ${X11_INCLUDE_DIR})
-  else()
-    include (FindOpenGL)
-    if (APPLE)
-      set (HAVE_GL_GLU_H ${HAVE_OPENGL_GLU_H})
-    endif (APPLE)
-  endif (OPTION_APPLE_X11)
+  include (FindOpenGL)
+  if (APPLE)
+    set (HAVE_GL_GLU_H ${HAVE_OPENGL_GLU_H})
+  endif (APPLE)
 else ()
   set (OPENGL_FOUND FALSE)
 endif (OPTION_USE_GL)
@@ -401,7 +378,7 @@ if (OPENGL_FOUND)
 
   if (WIN32)
     set (GLLIBS "-lglu32 -lopengl32")
-  elseif (APPLE AND NOT OPTION_APPLE_X11)
+  elseif (APPLE)
     set (GLLIBS "-framework OpenGL")
   else ()
     set (GLLIBS "-lGLU -lGL")
@@ -545,9 +522,6 @@ if (OPTION_USE_XFT)
   set (USE_XFT X11_Xft_FOUND)
   list (APPEND FLTK_LDLIBS -lXft)
   set (FLTK_XFT_FOUND TRUE)
-  if (APPLE AND OPTION_APPLE_X11)
-    find_library(LIB_fontconfig fontconfig "/opt/X11/lib")
-  endif (APPLE AND OPTION_APPLE_X11)
 else()
   set (FLTK_XFT_FOUND FALSE)
 endif (OPTION_USE_XFT)
diff --git a/CMake/resources.cmake b/CMake/resources.cmake
index 57173f206..bb059d9d2 100644
--- a/CMake/resources.cmake
+++ b/CMake/resources.cmake
@@ -163,9 +163,9 @@ mark_as_advanced (FREETYPE_PATH)
 #######################################################################
 # libraries
 find_library (LIB_dl dl)
-if ((NOT APPLE) OR OPTION_APPLE_X11)
+if (NOT APPLE)
   find_library (LIB_fontconfig fontconfig)
-endif ((NOT APPLE) OR OPTION_APPLE_X11)
+endif (NOT APPLE)
 find_library (LIB_freetype freetype)
 find_library (LIB_GL GL)
 find_library (LIB_MesaGL MesaGL)
diff --git a/CMake/setup.cmake b/CMake/setup.cmake
index 60b7da109..ea1a6ea16 100644
--- a/CMake/setup.cmake
+++ b/CMake/setup.cmake
@@ -59,7 +59,7 @@ set (FLTK_DOCDIR ${CMAKE_INSTALL_DATADIR}/doc CACHE PATH
 # set where config files go
 if (WIN32 AND NOT CYGWIN)
   set (FLTK_CONFIG_PATH CMake)
-elseif (APPLE AND NOT OPTION_APPLE_X11)
+elseif (APPLE)
   set (FLTK_CONFIG_PATH FLTK.framework/Resources/CMake)
 else ()
   set (FLTK_CONFIG_PATH ${FLTK_DATADIR}/fltk)
@@ -75,17 +75,9 @@ if (APPLE)
   set (HAVE_VSNPRINTF 1)
   set (HAVE_SCANDIR 1)
   set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated")
-  if (OPTION_APPLE_X11)
-    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -U__APPLE__")
-    set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -U__APPLE__")
-    if (NOT(${CMAKE_SYSTEM_VERSION} VERSION_LESS 17.0.0)) # a.k.a. macOS version ≥ 10.13
-      set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_LIBCPP_HAS_THREAD_API_PTHREAD")
-    endif (NOT(${CMAKE_SYSTEM_VERSION} VERSION_LESS 17.0.0))
-  else ()
-    set (__APPLE_QUARTZ__ 1)
-    set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -framework Cocoa")
-    set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -framework Cocoa")
-  endif (OPTION_APPLE_X11)
+  set (__APPLE_QUARTZ__ 1)
+  set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -framework Cocoa")
+  set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -framework Cocoa")
 endif (APPLE)
 
 if (WIN32)
diff --git a/CMake/variables.cmake b/CMake/variables.cmake
index 27672c7d5..0360d06d3 100644
--- a/CMake/variables.cmake
+++ b/CMake/variables.cmake
@@ -41,7 +41,7 @@ endif (DEBUG_VARIABLES_CMAKE)
 
 if (WIN32)
   list (APPEND FLTK_LDLIBS -lole32 -luuid -lcomctl32 -lws2_32)
-elseif (APPLE AND NOT OPTION_APPLE_X11)
+elseif (APPLE)
   list (APPEND FLTK_LDLIBS "-framework Cocoa")
 else ()
   list (APPEND FLTK_LDLIBS -lm)