Index: lldb/cmake/modules/LLDBConfig.cmake
===================================================================
--- lldb/cmake/modules/LLDBConfig.cmake
+++ lldb/cmake/modules/LLDBConfig.cmake
@@ -24,40 +24,47 @@
   set(LLDB_LINKER_SUPPORTS_GROUPS ON)
 endif()
 
+function(add_optional_dependency variable description package found)
+  set(${variable} "AUTO" CACHE STRING "${description} On, Off or Auto (default)")
+  string(TOUPPER "${${variable}}" ${variable})
+  if ("${${variable}}" STREQUAL "OFF")
+    set(${variable} OFF PARENT_SCOPE)
+  else()
+    if ("${${variable}}" STREQUAL "AUTO")
+      set(maybe_required)
+    else()
+      set(maybe_required REQUIRED)
+    endif()
+    find_package(${package} ${maybe_required})
+    # We could set ${variable} directory to ${${found}} but then the value is
+    # TRUE/FALSE rather than ON/OFF.
+    if (${${found}})
+      set(${variable} ON PARENT_SCOPE)
+    else()
+      set(${variable} OFF PARENT_SCOPE)
+    endif()
+  endif()
+endfunction()
+
+add_optional_dependency(LLDB_ENABLE_LIBEDIT "Enable editline support." LibEdit libedit_FOUND)
+add_optional_dependency(LLDB_ENABLE_CURSES "Enable curses support." Curses CURSES_FOUND)
+
 set(default_enable_python ON)
-set(default_enable_libedit ON)
-set(default_enable_curses ON)
 
 # Temporary support the old LLDB_DISABLE_* variables
-if (DEFINED LLDB_DISABLE_CURSES)
-  if (LLDB_DISABLE_CURSES)
-    set(default_enable_curses OFF)
-  endif()
-endif()
 if (DEFINED LLDB_DISABLE_PYTHON)
   if (LLDB_DISABLE_PYTHON)
     set(default_enable_python OFF)
   endif()
 endif()
 
-if(DEFINED LLVM_ENABLE_LIBEDIT AND NOT LLVM_ENABLE_LIBEDIT)
-  set(default_disable_libedit ON)
-endif()
-
-if(CMAKE_SYSTEM_NAME MATCHES "Windows")
-  set(default_enable_libedit OFF)
-  set(default_enable_curses OFF)
-elseif(CMAKE_SYSTEM_NAME MATCHES "Android")
+if(CMAKE_SYSTEM_NAME MATCHES "Android")
   set(default_enable_python OFF)
-  set(default_enable_libedit OFF)
-  set(default_enable_curses OFF)
 elseif(IOS)
   set(default_enable_python OFF)
 endif()
 
 option(LLDB_ENABLE_PYTHON "Enable Python scripting integration." ${default_enable_python})
-option(LLDB_ENABLE_LIBEDIT "Enable the use of editline." ${default_enable_libedit})
-option(LLDB_ENABLE_CURSES "Enable Curses integration." ${default_enable_curses})
 option(LLDB_RELOCATABLE_PYTHON "Use the PYTHONHOME environment variable to locate Python." OFF)
 option(LLDB_USE_SYSTEM_SIX "Use six.py shipped with system and do not install a copy of it" OFF)
 option(LLDB_USE_ENTITLEMENTS "When codesigning, use entitlements if available" ON)
@@ -120,12 +127,9 @@
   add_definitions( -DHAVE_ROUND )
 endif()
 
-
+# Check if we libedit capable of handling wide characters (built with
+# '--enable-widec').
 if (LLDB_ENABLE_LIBEDIT)
-  find_package(LibEdit REQUIRED)
-
-  # Check if we libedit capable of handling wide characters (built with
-  # '--enable-widec').
   set(CMAKE_REQUIRED_LIBRARIES ${libedit_LIBRARIES})
   set(CMAKE_REQUIRED_INCLUDES ${libedit_INCLUDE_DIRS})
   check_symbol_exists(el_winsertstr histedit.h LLDB_EDITLINE_USE_WCHAR)
@@ -141,7 +145,6 @@
   set(CMAKE_EXTRA_INCLUDE_FILES)
 endif()
 
-
 # On Windows, we can't use the normal FindPythonLibs module that comes with CMake,
 # for a number of reasons.
 # 1) Prior to MSVC 2015, it is only possible to embed Python if python itself was
@@ -498,10 +501,10 @@
 endif()
 
 if (LLDB_ENABLE_CURSES)
-    find_package(Curses REQUIRED)
     find_library(CURSES_PANEL_LIBRARY NAMES panel DOC "The curses panel library")
     if (NOT CURSES_PANEL_LIBRARY)
-        message(FATAL_ERROR "A required curses' panel library not found.")
+      set(LLDB_ENABLE_CURSES OFF)
+      message(WARNING "Curses panel library not found.")
     endif ()
 endif ()