Add 3.15.6 example app (for compilation tests)

exampleApp/src/initTrace.c

@@ -0,0 +1,39 @@
+/* initTrace.c */
+
+/*
+ * An initHook routine to trace the iocInit() process.
+ * Prints out the name of each state as it is reached.
+ */
+
+#include <stdio.h>
+
+#include "initHooks.h"
+#include "epicsExport.h"
+#include "iocsh.h"
+
+
+static void trace(initHookState state) {
+    printf("iocInit: Reached %s\n", initHookName(state));
+}
+
+int traceIocInit(void) {
+    static int done = 0;
+    if (done)
+        return -1;
+    done = 1;
+
+    initHookRegister(trace);
+    puts("iocInit will be traced");
+    return 0;
+}
+
+
+static const iocshFuncDef traceInitFuncDef = {"traceIocInit", 0, NULL};
+static void traceInitFunc(const iocshArgBuf *args) {
+    traceIocInit();
+}
+
+static void initTraceRegister(void) {
+    iocshRegister(&traceInitFuncDef, traceInitFunc);
+}
+epicsExportRegistrar(initTraceRegister);