diff --git a/os/access.c b/os/access.c
index 3856e606e..b7b19279f 100644
--- a/os/access.c
+++ b/os/access.c
@@ -1489,7 +1489,7 @@ InvalidHost (
     }
     for (host = validhosts; host; host = host->next)
     {
-	if ((host->family == FamilyServerInterpreted)) {
+	if (host->family == FamilyServerInterpreted) {
 	    if (siAddrMatch (family, addr, len, host, client)) {
 		return 0;
 	    }
diff --git a/os/log.c b/os/log.c
index 65195ba43..9579e58d8 100644
--- a/os/log.c
+++ b/os/log.c
@@ -102,6 +102,10 @@ OR PERFORMANCE OF THIS SOFTWARE.
 #include "xf86bigfontsrv.h"
 #endif
 
+#ifdef __clang__
+#pragma clang diagnostic ignored "-Wformat-nonliteral"
+#endif
+
 #ifdef DDXOSVERRORF
 void (*OsVendorVErrorFProc)(const char *, va_list args) = NULL;
 #endif
diff --git a/os/xstrans.c b/os/xstrans.c
index c086e225b..44ff976a9 100644
--- a/os/xstrans.c
+++ b/os/xstrans.c
@@ -2,6 +2,11 @@
 #include <dix-config.h>
 #endif
 
+#include <X11/Xfuncproto.h>
+
+/* ErrorF is used by xtrans */
+extern _X_EXPORT void ErrorF(const char *f, ...) _X_ATTRIBUTE_PRINTF(1,2);
+
 #define TRANS_REOPEN
 #define TRANS_SERVER
 #define XSERV_t