snownews doesn't use MacPorts CFLAGS and LDFLAGS

[ryandesign (Ryan Carsten Schmidt)]

snownews doesn't use MacPorts CFLAGS and LDFLAGS therefore it doesn't use the right -arch flags and the legacysupport flags don't get used.

​https://build.macports.org/builders/ports-10.11_x86_64-builder/builds/187551/steps/install-port/logs/stdio

/usr/bin/clang -o .o/snownews .o/about.o .o/categories.o .o/conversions.o .o/cookies.o .o/dialog.o .o/digcalc.o .o/filters.o .o/interface.o .o/io-internal.o .o/main.o .o/md5.o .o/net-support.o .o/netio.o .o/os-support.o .o/setup.o .o/ui-support.o .o/xmlparse.o .o/zlib_interface.o -liconv -lintl -lxml2 -lncurses -lz
Undefined symbols for architecture x86_64:
  "_clock_gettime", referenced from:
      _main in main.o
ld: symbol(s) not found for architecture x86_64