Port build to gcc -fcheck-pointer-bounds

This does not let Emacs run, just build.
* lib-src/etags.c (main):
* lib-src/profile.c (main):
Use return, not exit.
* src/bytecode.c (BYTE_CODE_THREADED) [__CHKP__]:
Do not define, as -fcheck-pointer-bounds is incompatible with taking
addresses of labels.
* src/menu.c (Fx_popup_dialog): Use eassume, not eassert,
to pacify gcc -fcheck-pointer-bounds -Wnull-dereference.

src/bytecode.c

@@ -46,7 +46,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    indirect threaded, using GCC's computed goto extension.  This code,
    as currently implemented, is incompatible with BYTE_CODE_SAFE and
    BYTE_CODE_METER.  */
-#if (defined __GNUC__ && !defined __STRICT_ANSI__ \
+#if (defined __GNUC__ && !defined __STRICT_ANSI__ && !defined __CHKP__ \
      && !BYTE_CODE_SAFE && !defined BYTE_CODE_METER)
 #define BYTE_CODE_THREADED
 #endif