call _exit instead of abort in release mode

Avoids cores being created, as they're nowadays often piped
to some call home system

contrib/epee/src/memwipe.c

@@ -31,6 +31,7 @@
 #define __STDC_WANT_LIB_EXT1__ 1
 #include <string.h>
 #include <stdlib.h>
+#include <unistd.h>
 #ifdef HAVE_EXPLICIT_BZERO
 #include <strings.h>
 #endif
@@ -50,7 +51,12 @@ void *memwipe(void *ptr, size_t n)
 {
   if (memset_s(ptr, n, 0, n))
   {
+#ifdef NDEBUG
+    fprintf(stderr, "Error: memset_s failed\n");
+    _exit(1);
+#else
     abort();
+#endif
   }
   SCARECROW // might as well...
   return ptr;