clang10 is unsupported

Version: Snapshot as of Thu Sep 12 17:55:54 CEST 2019
Platform: NetBSD
Subsystem: ?

clang10 (svn snapshot) is unsupported

ERROR: Did not find a new enough assembler, install one or build with
       --openssl-no-asm.
       Please refer to BUILDING.md
*** Error code 1

Culrpit code in configure.py:

def get_llvm_version(cc):
  return get_version_helper(
cc, r"(^(?:FreeBSD )?clang version|based on LLVM) ([3-9]\.[0-9]+)")

This patch fixes the problem for me:

-    cc, r"(^(?:FreeBSD )?clang version|based on LLVM) ([3-9]\.[0-9]+)")
+    cc, r"(^(?:FreeBSD )?clang version|based on LLVM) ((\d{2}|[3-9])\.[0-9]+)")

Maybe it would be reasonable to accept all LLVM versions now.