[gjs] build: Don't use the vptr sanitizer

[Philip Chimento <pchimento src gnome org>]

commit 1eb8dc484558bfb16bc195989d44adc2c5ce117f
Author: Philip Chimento <philip endlessm com>
Date:   Wed Aug 30 13:34:28 2017 -0700

    build: Don't use the vptr sanitizer
    
    SpiderMonkey compiles without runtime type information by default, and
    the vptr sanitizer (part of UBSan) is not compatible with that. This
    caused too many false positives to be useful.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786995

 configure.ac |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c99bb7e..6bbf733 100644
--- a/configure.ac
+++ b/configure.ac
@@ -220,9 +220,9 @@ AC_ARG_ENABLE([ubsan],
   [AS_HELP_STRING([--enable-ubsan], [Build with undefined behavior sanitizer support @<:@default: no@:>@])])
 
 AS_IF([test "x$enable_ubsan" = "xyes"], [
-  AX_CHECK_COMPILE_FLAG([-fsanitize=undefined -fno-omit-frame-pointer -g], [
-    AX_CHECK_LINK_FLAG([-fsanitize=undefined],
-      [SAN_FLAGS="$SAN_FLAGS -fsanitize=undefined"])
+  AX_CHECK_COMPILE_FLAG([-fsanitize=undefined -fno-sanitize=vptr -fno-omit-frame-pointer -g], [
+    AX_CHECK_LINK_FLAG([-fsanitize=undefined -fno-sanitize=vptr],
+      [SAN_FLAGS="$SAN_FLAGS -fsanitize=undefined -fno-sanitize=vptr"])
   ])
 ])