Assume dlerror() function is always available when dlopen() is

Remove separate checks for dlerror() which don't seem to be needed under
any platform any longer.

No real changes, just slim down configure/CMake a tiny bit.

configure

@@ -32744,63 +32744,6 @@ done
 
 
                         if test "$HAVE_DL_FUNCS" = 1; then
-                for ac_func in dlerror
-do :
-  ac_fn_c_check_func "$LINENO" "dlerror" "ac_cv_func_dlerror"
-if test "x$ac_cv_func_dlerror" = xyes; then :
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_DLERROR 1
-_ACEOF
- $as_echo "#define HAVE_DLERROR 1" >>confdefs.h
-
-else
-
-                        { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlerror in -ldl" >&5
-$as_echo_n "checking for dlerror in -ldl... " >&6; }
-if ${ac_cv_lib_dl_dlerror+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_check_lib_save_LIBS=$LIBS
-LIBS="-ldl  $LIBS"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char dlerror ();
-int
-main ()
-{
-return dlerror ();
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_dl_dlerror=yes
-else
-  ac_cv_lib_dl_dlerror=no
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext conftest.$ac_ext
-LIBS=$ac_check_lib_save_LIBS
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlerror" >&5
-$as_echo "$ac_cv_lib_dl_dlerror" >&6; }
-if test "x$ac_cv_lib_dl_dlerror" = xyes; then :
-  $as_echo "#define HAVE_DLERROR 1" >>confdefs.h
-
-fi
-
-
-
-fi
-done
-
                 for ac_func in dladdr
 do :
   ac_fn_c_check_func "$LINENO" "dladdr" "ac_cv_func_dladdr"