Fix build with cups>=2.2.0

--- prnt/hpijs/hpcupsfax.cpp.orig	Fri Aug 26 12:03:15 2016
+++ prnt/hpijs/hpcupsfax.cpp	Sun Sep 18 19:30:46 2016
@@ -43,6 +43,7 @@
 #include <arpa/inet.h>
 #include <math.h>
 #include <cups/cups.h>
+#include <cups/ppd.h>
 #include <cups/raster.h>
 #include <string>
 #ifdef FALSE
@@ -94,7 +95,7 @@ static void GetLogLevel ()
     FILE    *fp;
     char    str[258];
     char    *p;
-    fp = fopen ("/etc/cups/cupsd.conf", "r");
+    fp = fopen ("${SYSCONFDIR}/cups/cupsd.conf", "r");
     if (fp == NULL)
         return;
     while (!feof (fp))