Merge #12901: build: Show enabled sanitizers in configure output

01189ab build: Show enabled sanitizers in configure output (practicalswift)

Pull request description:

  Show enabled sanitizers in `configure` output.

  Context: @eklitzke excellent addition of `--with-sanitizers` in #12692

Tree-SHA512: b2d52308e3476488fe47cbc059d7f3235aaeefaa2b987003923f6eaacbadf67f0cf22a32a04873d0f54c1867757841e01c8053f86a4d2f59a407b960ac15105f

Author: MarcoFalke

configure.ac

@@ -1373,6 +1373,7 @@ echo "  with test     = $use_tests"
 echo "  with bench    = $use_bench"
 echo "  with upnp     = $use_upnp"
 echo "  use asm       = $use_asm"
+echo "  sanitizers    = $use_sanitizers"
 echo "  debug enabled = $enable_debug"
 echo "  gprof enabled = $enable_gprof"
 echo "  werror        = $enable_werror"