Add --no-malloc-fail parameter

So that the malloc failure configuration can be returned to non failure,
without using the full `--no-standard-checks` option.

Author: thomasspriggs

Diff for: src/util/config.cpp

@@ -1127,6 +1127,11 @@ bool configt::set(const cmdlinet &cmdline)
     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("no-malloc-fail"))
+  {
+    ansi_c.malloc_may_fail = false;
+    ansi_c.malloc_failure_mode = ansi_ct::malloc_failure_mode_none;
+  }
 
   if(cmdline.isset("c89"))
     ansi_c.set_c89();

Diff for: src/util/config.h

@@ -70,14 +70,15 @@ class symbol_table_baset;
     " {y--no-library} \t disable built-in abstract C library\n"
 
 #define OPT_CONFIG_LIBRARY                                                     \
-  "(malloc-fail-assert)(malloc-fail-null)(malloc-may-fail)"                    \
+  "(malloc-fail-assert)(malloc-fail-null)(malloc-may-fail)(no-malloc-fail)"    \
   "(string-abstraction)"
 
 #define HELP_CONFIG_LIBRARY                                                    \
   " {y--malloc-may-fail} \t allow malloc calls to return a null pointer\n"     \
   " {y--malloc-fail-assert} \t "                                               \
   "set malloc failure mode to assert-then-assume\n"                            \
   " {y--malloc-fail-null} \t set malloc failure mode to return null\n"         \
+  " {y--no-malloc-fail} \t Disable potential malloc failure.\n"                \
   " {y--string-abstraction} \t track C string lengths and zero-termination\n"
 
 #define OPT_CONFIG_JAVA "(classpath)(cp)(main-class)"