Index: auto.def
==================================================================
--- auto.def
+++ auto.def
@@ -537,10 +537,11 @@
 cc-check-functions utime
 cc-check-functions usleep
 cc-check-functions strchrnul
 cc-check-functions pledge
 cc-check-functions backtrace
+cc-check-functions kqueue
 
 # Check for getloadavg(), and if it doesn't exist, define FOSSIL_OMIT_LOAD_AVERAGE
 if {![cc-check-functions getloadavg]} {
   define FOSSIL_OMIT_LOAD_AVERAGE 1
   msg-result "Load average support unavailable"

Index: src/cgi.c
==================================================================
--- src/cgi.c
+++ src/cgi.c
@@ -33,11 +33,16 @@
 # include <netinet/in.h>
 # include <arpa/inet.h>
 # include <sys/times.h>
 # include <sys/time.h>
 # include <sys/wait.h>
-# include <sys/select.h>
+# if HAVE_KQUEUE
+#  include <errno.h>
+#  include <sys/event.h>
+# else
+#  include <sys/select.h>
+# endif
 #endif
 #ifdef __EMX__
   typedef int socklen_t;
 #endif
 #include <time.h>
@@ -1819,15 +1824,25 @@
   fossil_exit(1);
 #else
   int listener = -1;           /* The server socket */
   int connection;              /* A socket for each individual connection */
   int nRequest = 0;            /* Number of requests handled so far */
-  fd_set readfds;              /* Set of file descriptors for select() */
+  int hasdata = 0;             /* select() / kevent() got a new connection */
   socklen_t lenaddr;           /* Length of the inaddr structure */
   int child;                   /* PID of the child process */
   int nchildren = 0;           /* Number of child processes */
+  unsigned waitUsec = 100000;  /* Microseconds to wait in select() / kevent() */
+#if HAVE_KQUEUE
+  struct kevent event;         /* The file descriptor we are monitoring */
+  struct kevent tevent;        /* The event that has triggered */
+  int kq = -1;                 /* Queue descriptor return by kqueue() */
+  int krc = 0;                 /* Return code from kevent() */
+  struct timespec delay;       /* How long to wait inside kevent() */
+#else
+  fd_set readfds;              /* Set of file descriptors for select() */
   struct timeval delay;        /* How long to wait inside select() */
+#endif
   struct sockaddr_in inaddr;   /* The socket address */
   int opt = 1;                 /* setsockopt flag */
   int iPort = mnPort;
 
   while( iPort<=mxPort ){
@@ -1888,23 +1903,52 @@
 #endif
     if( system(zBrowser)<0 ){
       fossil_warning("cannot start browser: %s\n", zBrowser);
     }
   }
+
+#if HAVE_KQUEUE
+  delay.tv_sec = 0;
+  delay.tv_nsec = 1000 * waitUsec;
+  kq = kqueue();
+  if( kq==-1 ){
+    fossil_fatal("kqueue: %s", strerror(errno));
+  }
+  EV_SET(&event, listener, EVFILT_READ, EV_ADD, 0, 0, NULL);
+  krc = kevent(kq, &event, 1, NULL, 0, NULL);
+  if( krc==-1 || event.flags & EV_ERROR ){
+    fossil_fatal("kevent: %s", strerror(krc==-1 ? errno : event.data));
+  }
+#endif
+
   while( 1 ){
 #if FOSSIL_MAX_CONNECTIONS>0
     while( nchildren>=FOSSIL_MAX_CONNECTIONS ){
       if( wait(0)>=0 ) nchildren--;
     }
 #endif
+#if HAVE_KQUEUE
+    krc = kevent(kq, NULL, 0, &tevent, 1, &delay);
+    if( krc==-1 ){
+        fossil_fatal("kevent: %s", strerror(errno));
+    }
+    if( krc==1 ){
+      hasdata = 1;
+    }
+#else
     delay.tv_sec = 0;
-    delay.tv_usec = 100000;
+    delay.tv_usec = waitUsec;
     FD_ZERO(&readfds);
     assert( listener>=0 );
     FD_SET( listener, &readfds);
     select( listener+1, &readfds, 0, 0, &delay);
     if( FD_ISSET(listener, &readfds) ){
+      hasdata = 1;
+    }
+#endif
+    if( hasdata ){
+      hasdata = 0;
       lenaddr = sizeof(inaddr);
       connection = accept(listener, (struct sockaddr*)&inaddr, &lenaddr);
       if( connection>=0 ){
         child = fork();
         if( child!=0 ){