diff --git a/src/lib-index/mail-transaction-log-file.c b/src/lib-index/mail-transaction-log-file.c
index 9239a73ddc..2c810247b7 100644
--- a/src/lib-index/mail-transaction-log-file.c
+++ b/src/lib-index/mail-transaction-log-file.c
@@ -231,7 +231,7 @@ mail_transaction_log_init_hdr(struct mail_transaction_log *log,
 	hdr->hdr_size = sizeof(struct mail_transaction_log_header);
 	hdr->indexid = log->index->indexid;
 	hdr->create_stamp = ioloop_time;
-#if !WORDS_BIGENDIAN
+#ifndef WORDS_BIGENDIAN
 	hdr->compat_flags |= MAIL_INDEX_COMPAT_LITTLE_ENDIAN;
 #endif
 
diff --git a/src/lib/byteorder.h b/src/lib/byteorder.h
index 264d397d5d..e7912bdd1f 100644
--- a/src/lib/byteorder.h
+++ b/src/lib/byteorder.h
@@ -221,7 +221,7 @@ static inline uint##size##_t cpu##size##_to_cpu_unaligned(const void *in)\
 	return bswap;							\
 }
 
-#if WORDS_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 #define GEN(size)	__GEN(size, x)
 #else
 #define GEN(size)	__GEN(size, i_bswap_##size(x))
diff --git a/src/lib/sha1.c b/src/lib/sha1.c
index fb8247f60a..781e54b325 100644
--- a/src/lib/sha1.c
+++ b/src/lib/sha1.c
@@ -80,7 +80,7 @@ sha1_step(struct sha1_ctxt *ctxt)
 	size_t t, s;
 	uint32_t	tmp;
 
-#if !WORDS_BIGENDIAN
+#ifndef WORDS_BIGENDIAN
 	struct sha1_ctxt tctxt;
 	memmove(&tctxt.m.b8[0], &ctxt->m.b8[0], 64);
 	ctxt->m.b8[0] = tctxt.m.b8[3]; ctxt->m.b8[1] = tctxt.m.b8[2];
@@ -189,7 +189,7 @@ sha1_pad(struct sha1_ctxt *ctxt)
 	memset(&ctxt->m.b8[padstart], 0, padlen - 8);
 	COUNT += (padlen - 8);
 	COUNT %= 64;
-#if WORDS_BIGENDIAN
+#ifdef WORDS_BIGENDIAN
 	PUTPAD(ctxt->c.b8[0]); PUTPAD(ctxt->c.b8[1]);
 	PUTPAD(ctxt->c.b8[2]); PUTPAD(ctxt->c.b8[3]);
 	PUTPAD(ctxt->c.b8[4]); PUTPAD(ctxt->c.b8[5]);