build: allow clang 10+ in configure.py

Detected on NetBSD/amd64.

Fixes: #29536

PR-URL: #29541
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: David Carlier <[email protected]>
Reviewed-By: Jiawen Geng <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Richard Lau <[email protected]>

configure.py

@@ -705,7 +705,7 @@ def get_nasm_version(asm):
 
 def get_llvm_version(cc):
   return get_version_helper(
-    cc, r"(^(?:FreeBSD )?clang version|based on LLVM) ([3-9]\.[0-9]+)")
+    cc, r"(^(?:FreeBSD )?clang version|based on LLVM) ([0-9]+\.[0-9]+)")
 
 def get_xcode_version(cc):
   return get_version_helper(