diff -Naur cmake-3.18.2.orig/Modules/FindRuby.cmake cmake-3.18.2/Modules/FindRuby.cmake
--- cmake-3.18.2.orig/Modules/FindRuby.cmake	2020-09-08 13:30:51.129086854 +0000
+++ cmake-3.18.2/Modules/FindRuby.cmake	2020-09-10 07:10:56.679302608 +0000
@@ -300,14 +300,8 @@
   _RUBY_CONFIG_VAR("sitearchdir" Ruby_SITEARCH_DIR)
   _RUBY_CONFIG_VAR("sitelibdir" Ruby_SITELIB_DIR)
 
-  # vendor_ruby available ?
-  execute_process(COMMAND ${Ruby_EXECUTABLE} -r vendor-specific -e "print 'true'"
-    OUTPUT_VARIABLE Ruby_HAS_VENDOR_RUBY  ERROR_QUIET)
-
-  if(Ruby_HAS_VENDOR_RUBY)
-    _RUBY_CONFIG_VAR("vendorlibdir" Ruby_VENDORLIB_DIR)
-    _RUBY_CONFIG_VAR("vendorarchdir" Ruby_VENDORARCH_DIR)
-  endif()
+  _RUBY_CONFIG_VAR("vendorlibdir" RUBY_VENDORLIB_DIR)
+  _RUBY_CONFIG_VAR("vendorarchdir" RUBY_VENDORARCH_DIR)
 
   # save the results in the cache so we don't have to run ruby the next time again
   set(Ruby_VERSION_MAJOR    ${Ruby_VERSION_MAJOR}    CACHE PATH "The Ruby major version" FORCE)