Add new option --show-possible to valgrind for later use by valgrind_test.py ...

tools/valgrind/possible.patch

+Index: memcheck/mc_main.c
+===================================================================
+--- memcheck/mc_main.c  (revision 10536)
++++ memcheck/mc_main.c  (working copy)
+@@ -4658,6 +4658,7 @@
+ LeakCheckMode MC_(clo_leak_check)             = LC_Summary;
+ VgRes         MC_(clo_leak_resolution)        = Vg_HighRes;
+ Bool          MC_(clo_show_reachable)         = False;
++Bool          MC_(clo_show_possible)          = True;
+ Bool          MC_(clo_workaround_gcc296_bugs) = False;
+ Int           MC_(clo_malloc_fill)            = -1;
+ Int           MC_(clo_free_fill)              = -1;
+@@ -4711,6 +4712,7 @@
+ 
+        if VG_BOOL_CLO(arg, "--partial-loads-ok", MC_(clo_partial_loads_ok)) {}
+    else if VG_BOOL_CLO(arg, "--show-reachable",   MC_(clo_show_reachable))   {}
++   else if VG_BOOL_CLO(arg, "--show-possible",   MC_(clo_show_possible))   {}
+    else if VG_BOOL_CLO(arg, "--workaround-gcc296-bugs",
+                                             MC_(clo_workaround_gcc296_bugs)) {}
+ 
+@@ -4776,6 +4778,7 @@
+ "    --leak-check=no|summary|full     search for memory leaks at exit?  [summary]\n"
+ "    --leak-resolution=low|med|high   differentiation of leak stack traces [high]\n"
+ "    --show-reachable=no|yes          show reachable blocks in leak check? [no]\n"
++"    --show-possible=no|yes           show possibly lost blocks in leak check? [yes]\n"
+ "    --undef-value-errors=no|yes      check for undefined value errors [yes]\n"
+ "    --track-origins=no|yes           show origins of undefined values? [no]\n"
+ "    --partial-loads-ok=no|yes        too hard to explain here; see manual [no]\n"
+Index: memcheck/mc_include.h
+===================================================================
+--- memcheck/mc_include.h       (revision 10536)
++++ memcheck/mc_include.h       (working copy)
+@@ -390,6 +390,9 @@
+ /* In leak check, show reachable-but-not-freed blocks?  default: NO */
+ extern Bool MC_(clo_show_reachable);
+ 
++/* In leak check, show possibly-lost blocks?  default: YES */
++extern Bool MC_(clo_show_possible);
++
+ /* Assume accesses immediately below %esp are due to gcc-2.96 bugs.
+  * default: NO */
+ extern Bool MC_(clo_workaround_gcc296_bugs);
+Index: memcheck/mc_leakcheck.c
+===================================================================
+--- memcheck/mc_leakcheck.c     (revision 10536)
++++ memcheck/mc_leakcheck.c     (working copy)
+@@ -844,7 +844,8 @@
+       print_record = is_full_check &&
+                      ( MC_(clo_show_reachable) || 
+                        Unreached == lr->key.state || 
+-                       Possible  == lr->key.state );
++                       ( MC_(clo_show_possible) && 
++                         Possible  == lr->key.state ) );
+       is_suppressed = 
+          MC_(record_leak_error) ( tid, i+1, n_lossrecords, lr, print_record );
+