diff -ur dovecot-1.1.7/config.h.in dovecot-patch/config.h.in
--- dovecot-1.1.7/config.h.in	2008-11-23 16:16:57.000000000 -0600
+++ dovecot-patch/config.h.in	2008-12-16 20:34:01.000000000 -0600
@@ -458,9 +458,6 @@
 /* Define if you have ldap_start_tls_s */
 #undef LDAP_HAVE_START_TLS_S
 
-/* Index file compatibility flags */
-#undef MAIL_INDEX_COMPAT_FLAGS
-
 /* List of compiled in mail storages */
 #undef MAIL_STORAGES
 
diff -ur dovecot-1.1.7/configure.in dovecot-patch/configure.in
--- dovecot-1.1.7/configure.in	2008-11-23 16:16:26.000000000 -0600
+++ dovecot-patch/configure.in	2008-12-16 20:35:08.000000000 -0600
@@ -2164,15 +2164,18 @@
 
 dnl * currently just checking for endianess
 
-AC_C_BIGENDIAN
-
-if test $ac_cv_c_bigendian = yes; then
-	flags=0
-else
-	flags=1
-fi
-
-AC_DEFINE_UNQUOTED(MAIL_INDEX_COMPAT_FLAGS, $flags, Index file compatibility flags)
+dnl APPLE
+case "$host_os" in
+darwin*)
+	dnl The build system's endianness is not necessarily the same as
+	dnl the runtime system's endianness, thanks to the -arch gcc flag
+	dnl and fat binaries.  So leave the endianness determination up
+	dnl to gcc by using __BIG_ENDIAN__ which is set by -arch.
+	AC_DEFINE(WORDS_BIGENDIAN, __BIG_ENDIAN__, APPLE)
+	;;
+*)	AC_C_BIGENDIAN
+	;;
+esac
 
 dnl **
 dnl ** IPv6 support
diff -ur dovecot-1.1.7/src/lib/sha1.c dovecot-patch/src/lib/sha1.c
--- dovecot-1.1.7/src/lib/sha1.c	2008-10-26 10:03:45.000000000 -0500
+++ dovecot-patch/src/lib/sha1.c	2008-12-16 20:35:37.000000000 -0600
@@ -80,7 +80,7 @@
 	size_t t, s;
 	uint32_t	tmp;
 
-#ifndef WORDS_BIGENDIAN
+#if !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 @@
 	memset(&ctxt->m.b8[padstart], 0, padlen - 8);
 	COUNT += (padlen - 8);
 	COUNT %= 64;
-#ifdef WORDS_BIGENDIAN
+#if 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]);
@@ -235,7 +235,7 @@
 
 	digest = (uint8_t *)digest0;
 	sha1_pad(ctxt);
-#ifdef WORDS_BIGENDIAN
+#if WORDS_BIGENDIAN
 	memmove(digest, &ctxt->h.b8[0], 20);
 #else
 	digest[0] = ctxt->h.b8[3]; digest[1] = ctxt->h.b8[2];
diff -ur dovecot-1.1.7/src/lib-index/mail-index-map.c dovecot-patch/src/lib-index/mail-index-map.c
--- dovecot-1.1.7/src/lib-index/mail-index-map.c	2008-10-26 10:03:45.000000000 -0500
+++ dovecot-patch/src/lib-index/mail-index-map.c	2008-12-16 20:35:15.000000000 -0600
@@ -367,7 +367,7 @@
 {
         enum mail_index_header_compat_flags compat_flags = 0;
 
-#ifndef WORDS_BIGENDIAN
+#if !WORDS_BIGENDIAN
 	compat_flags |= MAIL_INDEX_COMPAT_LITTLE_ENDIAN;
 #endif
 
@@ -784,7 +784,7 @@
 	hdr->header_size = sizeof(*hdr);
 	hdr->record_size = sizeof(struct mail_index_record);
 
-#ifndef WORDS_BIGENDIAN
+#if !WORDS_BIGENDIAN
 	hdr->compat_flags |= MAIL_INDEX_COMPAT_LITTLE_ENDIAN;
 #endif
 
diff -ur dovecot-1.1.7/src/lib-index/mail-index.c dovecot-patch/src/lib-index/mail-index.c
--- dovecot-1.1.7/src/lib-index/mail-index.c	2008-10-26 10:03:45.000000000 -0500
+++ dovecot-patch/src/lib-index/mail-index.c	2008-12-16 20:35:31.000000000 -0600
@@ -633,7 +633,7 @@
         index->index_lock_timeout = FALSE;
 }
 
-#ifdef WORDS_BIGENDIAN
+#if WORDS_BIGENDIAN
 /* FIXME: Unfortunately these functions were originally written to use
    endian-specific code and we can't avoid that without breaking backwards
    compatibility. When we do break it, just select one of these. */