restore handler.c -- no compatibility mode, and hence no stack traces,

if execinfo.h is not present

src/Makefile.am

@@ -22,9 +22,8 @@ varnishevent_SOURCES = \
 	monitor.c \
 	strfTIM.h \
 	strfTIM.c \
-	format.c
-
-#	handler.c
+	format.c \
+	handler.c
 
 varnishevent_LDADD = \
 	${PTHREAD_LIBS} ${RT_LIBS} ${LIBM} @VARNISH_LIBS@ \

src/handler.c

@@ -42,10 +42,9 @@
 #include <syslog.h>
 #include <stdlib.h>
 #include <ctype.h>
+#include <errno.h>
 
-#ifndef HAVE_EXECINFO_H
-#include "compat/execinfo.h"
-#else
+#ifdef HAVE_EXECINFO_H
 #include <execinfo.h>
 #endif
 
@@ -67,6 +66,8 @@
  * +1 to phk's rant in varnishd.c about the lack of a standard for this.
  */
 
+#ifdef HAVE_EXECINFO_H
+
 struct symbols {
     uintptr_t               a;
     char                    *n;
@@ -165,19 +166,27 @@ stacktrace(void)
     }
 }
 
+#endif
+
 void
 HNDL_Init(const char *a0)
 {
+#ifdef HAVE_EXECINFO_H
     symbol_hack(a0);
+#else
+    (void) a0;
+#endif
 }
 
 void
 HNDL_Abort(int sig)
 {
     AZ(sigaction(SIGABRT, &default_action, NULL));
-    LOG_Log(LOG_ALERT, "Received signal %d (%s), stacktrace follows", sig,
-        strsignal(sig));
+    LOG_Log(LOG_ALERT, "Received signal %d (%s)", sig, strsignal(sig));
+#ifdef HAVE_EXECINFO_H
+    LOG_Log0(LOG_NOTICE, "Stacktrace follows");
     stacktrace();
+#endif
     CONF_Dump();
     DATA_Dump();
     MON_Output();

src/varnishevent.c

@@ -562,16 +562,12 @@ main(int argc, char *argv[])
     AZ(sigemptyset(&reopen_action.sa_mask));
     reopen_action.sa_flags |= SA_RESTART;
 
-#if 0
     stacktrace_action.sa_handler = HNDL_Abort;
-#endif
 
     ignore_action.sa_handler = SIG_IGN;
     default_action.sa_handler = SIG_DFL;
 
-#if 0
     HNDL_Init(argv[0]);
-#endif
 
     /* Install signal handlers */
 #include "signals.h"

src/varnishevent.h

@@ -296,10 +296,8 @@ int FMT_Estimate_RecsPerTx(void);
 void FMT_Format(tx_t *tx, struct vsb *os);
 void FMT_Fini(void);
 
-#if 0
 /* handler.c */
 void HNDL_Init(const char *a0);
 void HNDL_Abort(int sig);
-#endif
 
 #endif