userfaultfd is disabled in musl

--- a/cmake/helpers/configure.cmake
+++ b/cmake/helpers/configure.cmake
@@ -337,8 +337,6 @@
     set(DONT_DEPRECATE_SPRINTF 1)
     add_definitions(-DDONT_DEPRECATE_SPRINTF)
   endif ()
-
-  check_include_file("linux/userfaultfd.h" HAVE_USERFAULTFD_H)
 endif ()
 
 if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")