help compile when S != B

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Upstream-Status: Pending
Index: ssmtp-2.64/Makefile.in
===================================================================
--- ssmtp-2.64.orig/Makefile.in
+++ ssmtp-2.64/Makefile.in
@@ -24,7 +24,7 @@ INSTALLED_REVALIASES_FILE=$(REVALIASES_F
 # Programs
 GEN_CONFIG=$(srcdir)/generate_config
 
-SRCS=ssmtp.c arpadate.c base64.c xgethostname.c @SRCS@
+SRCS=$(srcdir)/ssmtp.c $(srcdir)/arpadate.c $(srcdir)/base64.c $(srcdir)/xgethostname.c @SRCS@
 
 OBJS=$(SRCS:.c=.o)