$NetBSD$

Don't build singleheader version of simduft.
The singleheader is not installed and not
building it removes dependecy on python.

--- CMakeLists.txt.orig	2023-11-15 22:34:03.000000000 +0000
+++ CMakeLists.txt
@@ -33,7 +33,6 @@ option(SIMDUTF_ICONV "Whether to use ico
 set(SIMDUTF_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 add_subdirectory(src)
-add_subdirectory(singleheader)
 
 if (SIMDUTF_TESTS)
   message(STATUS "The tests are enabled.")