examples: support libev and fix build on Fedora

Check for and prefer libev over libevent and check for the location
of the event.h file, which is contained in libev/event.h on Fedora.

Signed-off-by: Patrick McHardy <kaber@trash.net>

Makefile.defs.in

@@ -41,3 +41,6 @@ CFLAGS		+= -Waggregate-return -Wunused -Wwrite-strings
 ifeq ($(DEBUG),y)
 CFLAGS		+= -g -DDEBUG
 endif
+
+EVENT_CFLAGS	+= @EVENT_CFLAGS@
+EVENT_LDFLAGS	+= @EVENT_LDFLAGS@

configure.ac

@@ -32,6 +32,14 @@ AC_CHECK_LIB([nl], [nl_socket_alloc], ,
 AC_CHECK_LIB([nl-dect], [nl_dect_cluster_alloc], ,
 	     AC_MSG_ERROR([No suitable version of libnl-dect found]))
 
+AC_CHECK_LIB(ev, event_init,
+	     [EVENTLIB="-lev"],
+	     AC_CHECK_LIB(event, event_init,
+			  [EVENTLIB="-levent"],
+			  AC_ERROR(libev or libevent not found)))
+EVENT_LDFLAGS=$EVENTLIB
+AC_SUBST(EVENT_LDFLAGS)
+
 # Checks for header files.
 AC_HEADER_STDC
 AC_HEADER_ASSERT
@@ -43,6 +51,14 @@ AC_CHECK_HEADERS([linux/dect.h linux/dect_netlink.h], ,
 		 AC_MSG_ERROR([DECT kernel header files not found]),
 		 [#include <sys/socket.h>])
 
+AC_CHECK_HEADER(event.h,
+		[EVENTINC="-include event.h"],
+		AC_CHECK_HEADER(libev/event.h,
+				[EVENTINC="-include libev/event.h"],
+				AC_MSG_ERROR([event.h not found])))
+EVENT_CFLAGS=$EVENTINC
+AC_SUBST(EVENT_CFLAGS)
+
 # Checks for typedefs, structures, and compiler characteristics.
 AC_HEADER_STDBOOL
 AC_C_CONST

example/Makefile.in

@@ -1,4 +1,5 @@
-LDFLAGS		+= -Wl,-rpath $(PWD)/src -Lsrc -ldect -levent
+CFLAGS		+= $(EVENT_CFLAGS)
+LDFLAGS		+= -Wl,-rpath $(PWD)/src -Lsrc -ldect $(EVENT_LDFLAGS)
 PROGRAMS	+= cc ss mm-fp mm-pp discover hijack
 
 destdir		:= usr/share/dect/examples

example/event_ops.c

@@ -2,7 +2,6 @@
 #include <sys/types.h>
 #include <sys/time.h>
 #include <signal.h>
-#include <event.h>
 
 #include <libdect.h>
 #include "common.h"