Add missing "\" that causes problems with some "make"'s, including

Solaris make

This commit was SVN r1101.

src/event/Makefile.am

@@ -18,7 +18,7 @@ EXTRA_DIST = err.c event.h evsignal.h event.3 kqueue.c \
 	epoll_sub.c epoll.c select.c rtsig.c poll.c signal.c
 
 # LAM: This causes problems
-junk =
+junk = \
 	sample/Makefile.am sample/Makefile.in sample/event-test.c \
 	sample/signal-test.c sample/time-test.c \
 	test/Makefile.am test/Makefile.in test/bench.c test/regress.c \