Use malloc-fail-null as the default model configuration

Author: thomasspriggs

Diff for: src/util/config.cpp

@@ -1126,7 +1126,10 @@ bool configt::set(const cmdlinet &cmdline)
   if(cmdline.isset("malloc-fail-assert"))
     ansi_c.malloc_failure_mode = ansi_c.malloc_failure_mode_assert_then_assume;
 
-  ansi_c.malloc_may_fail = cmdline.isset("malloc-may-fail");
+  if(cmdline.isset("malloc-may-fail"))
+  {
+    ansi_c.malloc_may_fail = true;
+  }
   if(cmdline.isset("no-malloc-fail"))
   {
     ansi_c.malloc_may_fail = false;

Diff for: src/util/config.h

@@ -272,7 +272,7 @@ class configt
     libt lib;
 
     bool string_abstraction;
-    bool malloc_may_fail = false;
+    bool malloc_may_fail = true;
 
     enum malloc_failure_modet
     {
@@ -281,7 +281,7 @@ class configt
       malloc_failure_mode_assert_then_assume = 2
     };
 
-    malloc_failure_modet malloc_failure_mode = malloc_failure_mode_none;
+    malloc_failure_modet malloc_failure_mode = malloc_failure_mode_return_null;
 
     static const std::size_t default_object_bits = 8;