Disable shared objects with threads

cmake/wasi-sdk-sysroot.cmake

@@ -148,10 +148,11 @@ function(define_wasi_libc_sub target target_suffix lto)
   set(extra_make_flags default)
 
   # If LTO is enabled then pass that on to wasi-libc, and otherwise make sure to
-  # build a `libc.so` dynamic library.
+  # build a `libc.so` dynamic library where possible (not compatible with
+  # threads though)
   if(lto)
     list(APPEND extra_make_flags LTO=full)
-  else()
+  elseif(NOT ${target} MATCHES threads)
     list(APPEND extra_make_flags libc_so)
   endif()