Linux (& unix/Mac OS X):

Fix the build of the XDisplayControlPlugin on linuxes where .so is not appended
to shared objects.
Fix the language in sqUnixHeartbeat.c and add more information.  Make the code
exclusive to linux, and use exeName instead of a hardwired name.

platforms/unix/plugins/XDisplayControlPlugin/Makefile.inc

@@ -1,8 +1,3 @@
 XCPPFLAGS= -I$(topdir)/platforms/Cross/plugins/FilePlugin -I$(topdir)/platforms/Cross/plugins/SocketPlugin
 XINCLUDES= $(X_INCLUDES)
-XLDFLAGS= $(X_LIBS) -L. -lvm-display-X11
-
-$(TARGET):	libvm-display-X11.so
-
-libvm-display-X11.so:
-	ln -s ../vm-display-X11/.libs/vm-display-X11.so libvm-display-X11.so
+XLDFLAGS= $(X_LIBS) -L ../vm-display-X11/.libs -lvm-display-X11

platforms/unix/vm/sqUnixHeartbeat.c

@@ -297,42 +297,45 @@ static volatile machine_state beatState = nascent;
 static int beatMilliseconds = DEFAULT_BEAT_MS;
 static struct timespec beatperiod = { 0, DEFAULT_BEAT_MS * 1000 * 1000 };
 
+#if __linux__
+# include "sqUnixMain.h"
+#endif
+
 static void *
 beatStateMachine(void *careLess)
 {
 	int er;
 	if ((er = pthread_setschedparam(pthread_self(),
 									stateMachinePolicy,
 									&stateMachinePriority))) {
+		extern char *revisionAsString();
+		errno = er;
+		perror("pthread_setschedparam failed");
+#if __linux__
 		/* Linux pthreads as of 2009 does not support setting the priority of
 		 * threads other than with real-time scheduling policies.  But such
 		 * policies are only available to processes with superuser privileges.
 		 * Linux kernels >= 2.6.13 support different thread priorities, but
 		 * require a suitable /etc/security/limits.d/VMNAME.conf.
 		 */
-		extern char *revisionAsString();
-		errno = er;
-		perror("pthread_setschedparam failed");
-#if PharoVM
-# define VMNAME "pharo"
-#elif NewspeakVM
-# define VMNAME "nsvm"
-#else
-# define VMNAME "squeak"
-#endif
-		fprintf(stderr, "This VM uses a thread heartbeat who requires a special configuration to work.\n");
-		fprintf(stderr, "You need to allow it to run higher priority threads (real time), to allow clock to work properly\n");
-		fprintf(stderr, "You need to add a conf file to /etc/security/limits.d, executing this:\n\n");
-		fprintf(stderr, "sudo cat >/etc/security/limits.d/%s.conf <<END\n", VMNAME);
+		fprintf(stderr, "This VM uses a heartbeat thread which requires a special configuration to work.\n");
+		fprintf(stderr, "It must be allowed to run higher priority threads for the clock and interrupts\n");
+		fprintf(stderr, "to work properly. To do this, add a conf file to /etc/security/limits.d by\n");
+		fprintf(stderr,"executing this:\n\n");
+		fprintf(stderr, "sudo cat >/etc/security/limits.d/%s.conf <<END\n", exeName);
 		fprintf(stderr, "*       hard    rtprio  2\n");
 		fprintf(stderr, "*       soft    rtprio  2\n");
 		fprintf(stderr, "END\n");
-		fprintf(stderr, "\nYou need to log out and log back in for the limits to take effect.\n");
-		fprintf(stderr, "For more information read https://github.com/OpenSmalltalk/opensmalltalk-vm/releases/tag/r3732#linux\n");
+		fprintf(stderr, "\nLog out and back in for the limits to take effect. For more information read\n");
+		fprintf(stderr, "  https://github.com/OpenSmalltalk/opensmalltalk-vm/releases/tag/r3732#linux\n");
+		fprintf(stderr, "  http://forum.world.st/Unix-heartbeat-thread-vs-itimer-td4928943.html\n");
 		// The VM may have issues with clock jitter due to the heartbeat thread
 		// not running at elevated priority. An exit may be appropriate in some
 		// cases, but for most users the above warning is sufficient.
 		// exit(errno);
+#else
+		exit(errno);
+#endif
 	}
 	beatState = active;
 	while (beatState != condemned) {