Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -53,7 +53,7 @@ option(YOSYS_WITHOUT_ZLIB "Disable zlib integration" O
 option(YOSYS_WITHOUT_LIBFFI "Disable libffi integration" OFF)
 option(YOSYS_WITHOUT_READLINE "Disable readline integration" OFF)
 option(YOSYS_WITHOUT_EDITLINE "Disable editline integration" OFF)
-option(YOSYS_WITHOUT_SLANG "Disable Slang integration" OFF)
+option(YOSYS_WITHOUT_SLANG "Disable Slang integration" ON)
 option(YOSYS_WITHOUT_TCL "Disable Tcl integration" OFF)
 option(YOSYS_WITH_PYTHON "Enable Python integration" OFF)
 
@@ -174,7 +174,7 @@ if (APPLE)
 	use_homebrew()
 endif()
 
-find_package(FLEX 2.6)
+find_package(FLEX 2.5.39)
 set_package_properties(FLEX PROPERTIES
 	URL "https://github.com/westes/flex"
 	DESCRIPTION "The Fast Lexical Analyzer"
