diff --git a/os/WaitFor.c b/os/WaitFor.c
index 992962df4b..6782667eff 100644
--- a/os/WaitFor.c
+++ b/os/WaitFor.c
@@ -393,12 +393,12 @@ TimerInit(void)
 #ifdef DPMSExtension
 
 #define DPMS_CHECK_MODE(mode,time)\
-    if (time > 0 && DPMSPowerLevel < mode && timeout >= time)\
-	DPMSSet(serverClient, mode);
+    if ((time) > 0 && DPMSPowerLevel < (mode) && timeout >= (time))\
+	DPMSSet(serverClient, (mode));
 
 #define DPMS_CHECK_TIMEOUT(time)\
-    if (time > 0 && (time - timeout) > 0)\
-	return time - timeout;
+    if ((time) > 0 && ((time) - timeout) > 0)\
+	return (time) - timeout;
 
 static CARD32
 NextDPMSTimeout(INT32 timeout)
diff --git a/os/Xtransutil.c b/os/Xtransutil.c
index f01b8fb510..6e08c36e8a 100644
--- a/os/Xtransutil.c
+++ b/os/Xtransutil.c
@@ -226,7 +226,7 @@ int _XSERVTransConvertAddress(int *familyp, int *addrlenp, Xtransaddr **addrp)
 
 #if !defined(S_IFLNK) && !defined(S_ISLNK)
 #undef lstat
-#define lstat(a,b) stat(a,b)
+#define lstat(a,b) stat((a),(b))
 #endif
 
 #define FAIL_IF_NOMODE  1
diff --git a/os/access.c b/os/access.c
index 0fab37466f..60b732ca1f 100644
--- a/os/access.c
+++ b/os/access.c
@@ -190,7 +190,7 @@ Bool defeatAccessControl = FALSE;
 #define addrEqual(fam, address, length, host) \
 			 ((fam) == (host)->family &&\
 			  (length) == (host)->len &&\
-			  !memcmp (address, (host)->addr, length))
+			  !memcmp ((address), (host)->addr, (length)))
 
 static int ConvertAddr(struct sockaddr * /*saddr */ ,
                        int * /*len */ ,
@@ -221,11 +221,11 @@ typedef struct _host {
 } HOST;
 
 #define MakeHost(h,l)	(h)=calloc(1, sizeof *(h)+(l));\
-			if (h) { \
+			if ((h)) { \
 			   (h)->addr=(unsigned char *) ((h) + 1);\
 			   (h)->requested = FALSE; \
 			}
-#define FreeHost(h)	free(h)
+#define FreeHost(h)	free((h))
 static HOST *selfhosts = NULL;
 static HOST *validhosts = NULL;
 static int AccessEnabled = TRUE;
@@ -526,9 +526,9 @@ DefineSelf(int fd)
 
 #ifdef VARIABLE_IFREQ
 #define ifr_size(p) (sizeof (struct ifreq) + \
-		     (p->ifr_addr.sa_len > sizeof (p->ifr_addr) ? \
-		      p->ifr_addr.sa_len - sizeof (p->ifr_addr) : 0))
-#define ifraddr_size(a) (a.sa_len)
+		     ((p)->ifr_addr.sa_len > sizeof ((p)->ifr_addr) ? \
+		      (p)->ifr_addr.sa_len - sizeof ((p)->ifr_addr) : 0))
+#define ifraddr_size(a) ((a).sa_len)
 #else
 #define ifr_size(p) (sizeof (ifr_type))
 #define ifraddr_size(a) (sizeof (a))
diff --git a/os/bug_priv.h b/os/bug_priv.h
index 7fc8b307af..a06dc5624d 100644
--- a/os/bug_priv.h
+++ b/os/bug_priv.h
@@ -14,20 +14,20 @@
         xorg_backtrace();                                             \
     } } while(0)
 
-#define BUG_WARN_MSG(cond, ...) __BUG_WARN_MSG(cond, 1, __VA_ARGS__)
+#define BUG_WARN_MSG(cond, ...) __BUG_WARN_MSG((cond), 1, __VA_ARGS__)
 
-#define BUG_WARN(cond)  __BUG_WARN_MSG(cond, 0, NULL)
+#define BUG_WARN(cond)  __BUG_WARN_MSG((cond), 0, NULL)
 
 #define BUG_RETURN(cond) \
-    do { if (cond) { __BUG_WARN_MSG(cond, 0, NULL); return; } } while(0)
+    do { if (cond) { __BUG_WARN_MSG((cond), 0, NULL); return; } } while(0)
 
 #define BUG_RETURN_MSG(cond, ...) \
-    do { if (cond) { __BUG_WARN_MSG(cond, 1, __VA_ARGS__); return; } } while(0)
+    do { if (cond) { __BUG_WARN_MSG((cond), 1, __VA_ARGS__); return; } } while(0)
 
 #define BUG_RETURN_VAL(cond, val) \
-    do { if (cond) { __BUG_WARN_MSG(cond, 0, NULL); return (val); } } while(0)
+    do { if (cond) { __BUG_WARN_MSG((cond), 0, NULL); return (val); } } while(0)
 
 #define BUG_RETURN_VAL_MSG(cond, val, ...) \
-    do { if (cond) { __BUG_WARN_MSG(cond, 1, __VA_ARGS__); return (val); } } while(0)
+    do { if (cond) { __BUG_WARN_MSG((cond), 1, __VA_ARGS__); return (val); } } while(0)
 
 #endif /* _XSERVER_OS_BUG_H_ */
diff --git a/os/cmdline.h b/os/cmdline.h
index eba96746f1..408a6a8f71 100644
--- a/os/cmdline.h
+++ b/os/cmdline.h
@@ -8,7 +8,7 @@
 #include "include/os.h"
 
 #define CHECK_FOR_REQUIRED_ARGUMENTS(num)  \
-    do if (((i + num) >= argc) || (!argv[i + num])) {                   \
+    do if (((i + (num)) >= argc) || (!argv[i + (num)])) {                   \
         UseMsg();                                                       \
         FatalError("Required argument to %s not specified\n", argv[i]); \
     } while (0)
diff --git a/os/xdmauth.c b/os/xdmauth.c
index abbb6144f5..4f4504dc38 100644
--- a/os/xdmauth.c
+++ b/os/xdmauth.c
@@ -115,9 +115,9 @@ XdmAuthenticationAddAuth(int name_len, const char *name,
     return ret;
 }
 
-#define atox(c)	('0' <= c && c <= '9' ? c - '0' : \
-		 'a' <= c && c <= 'f' ? c - 'a' + 10 : \
-		 'A' <= c && c <= 'F' ? c - 'A' + 10 : -1)
+#define atox(c)	('0' <= (c) && (c) <= '9' ? (c) - '0' : \
+		 'a' <= (c) && (c) <= 'f' ? (c) - 'a' + 10 : \
+		 'A' <= (c) && (c) <= 'F' ? (c) - 'A' + 10 : -1)
 
 static int
 HexToBinary(const char *in, char *out, int len)
diff --git a/os/xserver_poll.h b/os/xserver_poll.h
index 8d8063a116..51136b156b 100644
--- a/os/xserver_poll.h
+++ b/os/xserver_poll.h
@@ -31,7 +31,7 @@
 
 #ifdef HAVE_POLL
 #include <poll.h>
-#define xserver_poll(fds, nfds, timeout) poll(fds, nfds, timeout)
+#define xserver_poll(fds, nfds, timeout) poll((fds), (nfds), (timeout))
 #else
 
 #ifdef WIN32