configure: support sanitizers

It is now possible to run ./configure --with-sanitizer=address
(or any least of valid sanitizers) to build with sanitizers.

When --with-sanitizer is specified, we build with -O1 and
don't omit frame-pointer. We also enable RTTI (which should
be enabled anyway, but just in case).

UBSan (undefined) sanitizer can cause 'typeinfo' errors.
Fixing the source is best, but as a workaround, disabling
vptr sanitizer works. Just pass -fno-sanitize=vptr to CFLAGS
and CXXFLAGS.

Change-Id: I4031aa872b1b1ef779703135394f3733952e5cd1
Reviewed-on: https://gerrit.libreoffice.org/79329
Reviewed-by: Ashod Nakashian <ashnakash@gmail.com>
Tested-by: Ashod Nakashian <ashnakash@gmail.com>

configure.ac

@@ -184,6 +184,10 @@ AC_ARG_WITH([max-documents],
              AS_HELP_STRING([--with-max-documents],
                            [Set the limit on the total number of documents. Def: 10, Min: 2.]))
 
+AC_ARG_WITH([sanitizer],
+             AS_HELP_STRING([--with-sanitizer],
+                           [Enable one or more compatible sanitizers. E.g. --with-sanitizer=address,undefined,leak]))
+
 AC_ARG_WITH([compiler-plugins],
             AS_HELP_STRING([--with-compiler-plugins=<path>],
                 [Experimental! Unlikely to work for anyone except Noel! Enable compiler plugins that will perform additional checks during
@@ -460,6 +464,16 @@ else
     AC_MSG_RESULT([no])
 fi
 
+AC_MSG_CHECKING([whether to turn sanitizers on])
+if test "x$with_sanitizer" != "x"; then
+    AC_MSG_RESULT([yes ($with_sanitizer)])
+    SANITIZER_FLAGS="-O1 -fno-omit-frame-pointer -fsanitize=$with_sanitizer -frtti -static-libasan"
+    CXXFLAGS="$CXXFLAGS $SANITIZER_FLAGS"
+    CFLAGS="$CFLAGS $SANITIZER_FLAGS"
+else
+    AC_MSG_RESULT([no])
+fi
+
 # check for C++11 support
 HAVE_CXX11=
 AC_MSG_CHECKING([whether $CXX supports C++14 or C++11])