netresolv: Fix build issues under Ubuntu 16.04 and OS X

* Either gcc or bison version changes are throwing a
  sign-compare Werror in the generateda irs nslexer.c
* This simply targets that Werror and disabled it in irs

src/kits/network/netresolv/Jamfile

@@ -24,8 +24,8 @@ for architectureObject in [ MultiArchSubDirSetup ] {
 			# we also need to use our BSD compatibility functions
 			local defines = _REENTRANT=1 USE_MD5=1 _BSD_SOURCE INET6 ;
 			defines = [ FDefines $(defines) ] ;
-			SubDirCcFlags $(defines) ;
-			SubDirC++Flags $(defines) ;
+			SubDirCcFlags $(defines) -Wno-error=sign-compare ;
+			SubDirC++Flags $(defines) -Wno-error=sign-compare ;
 		}
 
 		MergeObject <netresolv!$(architecture)>netresolv.o :