stub ffi for Mac OSX PPC

[[Split portion of a mixed commit.]]

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
 
 

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)