diff --git a/source/texk/web2c/luatexdir/luaffi/ffi.h b/source/texk/web2c/luatexdir/luaffi/ffi.h
index 75fe9c8a87a5b9b7941d9246c7aa5a593178e3ce..7c9242c7eb6fa1626bc89cc08b0c9a01088411b9 100644
--- a/source/texk/web2c/luatexdir/luaffi/ffi.h
+++ b/source/texk/web2c/luatexdir/luaffi/ffi.h
@@ -142,7 +142,7 @@ static void (lua_remove)(lua_State *L, int idx) {
 #elif defined __powerpc64__
 # define ARCH_PPC64
 #else
-# error
+# define UNSUPPORTED_ARCH
 #endif
 
 
diff --git a/source/texk/web2c/luatexdir/luatex.c b/source/texk/web2c/luatexdir/luatex.c
index 7e62b59b5f7346fff46f645eee964d24dd0fbd78..7933d17d6df1faa48c7c0ed43ad4bee73b873ccb 100644
--- a/source/texk/web2c/luatexdir/luatex.c
+++ b/source/texk/web2c/luatexdir/luatex.c
@@ -198,7 +198,7 @@ void init_start_time(void) {
         if (source_date_epoch && source_date_epoch != '\0' ) {
             errno = 0;
             epoch = strtoull(source_date_epoch, &endptr, 10);
-            if (epoch < 0 || *endptr != '\0' || errno != 0) {
+            if (*endptr != '\0' || errno != 0) {
                 epoch = 0;
             }
 #if defined(_MSC_VER)