Added the first of S.J. Moller's (sjm@nwc.dk) proposed changes for Solaris 2.6.

config/SunOS5.mk

@@ -91,7 +91,7 @@ PORT_FLAGS		+= -D_SVID_GETTOD
 endif
 ifeq ($(OS_VERSION),.6)
 PLATFORM_FLAGS		+= -DSOLARIS2_6 -DSOLARIS_55_OR_GREATER -DSOLARIS_56_OR_GREATER
-PORT_FLAGS		+= -D_SVID_GETTOD
+PORT_FLAGS		+= -D_SVID_GETTOD -DHAVE_SNPRINTF
 else
 PORT_FLAGS		+= -DNEED_INET_TCP_H
 endif