diff --git a/src/libsodium/crypto_pwhash/scryptsalsa208sha256/crypto_scrypt.h b/src/libsodium/crypto_pwhash/scryptsalsa208sha256/crypto_scrypt.h
index 47a30f78..2100ecc7 100644
--- a/src/libsodium/crypto_pwhash/scryptsalsa208sha256/crypto_scrypt.h
+++ b/src/libsodium/crypto_pwhash/scryptsalsa208sha256/crypto_scrypt.h
@@ -32,7 +32,7 @@
 
 #include <stdint.h>
 
-#if SIZE_MAX > 0xffffffffUL
+#if SIZE_MAX > 0xffffffffULL
 # define ARCH_BITS 64
 #else
 # define ARCH_BITS 32