security/doscan: Fix build with Clang 6

src/event_queue.cc:161:43: error: invalid operands to binary expression
      ('basic_ostream<char, std::__1::char_traits<char> >' and 'std::__1::ostream'
      (aka 'basic_ostream<char>'))
    std::cerr << "No handlers installed." << std::cerr;
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~

http://beefy11.nyi.freebsd.org/data/head-i386-default/p477696_s338122/logs/errors/doscan-0.3.3_1.log

- Make sure the build respects CXXFLAGS

security/doscan/Makefile

@@ -17,6 +17,7 @@ LIB_DEPENDS=	libpcre.so:devel/pcre
 
 GNU_CONFIGURE=	yes
 USES=		gmake
+USE_CXXSTD=	gnu++98
 
 PORTDOCS=	README
 PLIST_FILES=	bin/doscan man/man1/doscan.1.gz

security/doscan/files/patch-Makefile.in

@@ -0,0 +1,17 @@
+--- Makefile.in.orig	2014-10-22 17:14:35 UTC
++++ Makefile.in
+@@ -85,12 +85,12 @@ stamp-dir :
+ 	echo timestamp > stamp-dir
+ 
+ src/%.o : $(srcdir)/src/%.cc
+-	$(CXX) $(CFLAGS) $(PCRE_CFLAGS) $(INCLUDES) \
++	$(CXX) $(CXXFLAGS) $(PCRE_CFLAGS) $(INCLUDES) \
+ 		-MMD -MF $(patsubst %.o,%.d, $@) \
+ 		-c -o $@ $<
+ 
+ src/%.o : src/%.cc
+-	$(CXX) $(CFLAGS) $(PCRE_CFLAGS) $(INCLUDES) \
++	$(CXX) $(CXXFLAGS) $(PCRE_CFLAGS) $(INCLUDES) \
+ 		-MMD -MF $(patsubst %.o,%.d, $@) \
+ 		-c -o $@ $<
+