kc3-lang/libtommath

diff --git a/tommath_private.h b/tommath_private.h
index c64fb92..67ac014 100644
--- a/tommath_private.h
+++ b/tommath_private.h
@@ -83,7 +83,7 @@ do {                                                    \
    size_t zs_ = (size);                                 \
    char* zm_ = (char*)(mem);                            \
    while (zs_-- > 0u) {                                 \
-      *zm_++ = 0;                                       \
+      *zm_++ = '\0';                                    \
    }                                                    \
 } while (0)
 #  define MP_ZERO_DIGITS(mem, digits)                   \