Add --enable-asan & --enable-ubsan. By default disabled.

configure.ac

@@ -185,6 +185,10 @@ if test x$enable_debug = xyes; then
  user_CXXFLAGS="$CXXFLAGS" # ac_save_CXXFLAGS is not set yet
 fi
 
+# sanitizer
+AC_ARG_ENABLE(asan, [ --enable-asan address sanitizer])
+AC_ARG_ENABLE(ubsan, [ --enable-ubsan undefined behaviour sanitizer])
+
 # do we want the bzflag client?
 AC_ARG_ENABLE(client, [ --disable-client server-only build])
 
@@ -767,6 +771,16 @@ else
  AC_DEFINE(NDEBUG, 1, [Debugging disabled])
 fi
 
+if test "x$enable_asan" = xyes; then
+ CONF_CFLAGS="$CONF_CFLAGS -fsanitize=address"
+ CONF_CXXFLAGS="$CONF_CXXFLAGS -fsanitize=address"
+fi
+
+if test "x$enable_ubsan" = xyes; then
+ CONF_CFLAGS="$CONF_CFLAGS -fsanitize=undefined -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow"
+ CONF_CXXFLAGS="$CONF_CXXFLAGS -fsanitize=undefined -fsanitize=float-divide-by-zero -fsanitize=float-cast-overflow"
+fi
+
 dnl check for -search_paths_first linker flag when making dynamic libraries
 search_paths_first_flag="-Wl,-search_paths_first -mdynamic-no-pic"
 AC_MSG_CHECKING([if the compiler understands $search_paths_first_flag])