add HAVE_LIBJUICE to config.h instead of cmd opt

Added -DHAVE_LIBJUICE to config.h instead of passing as a compiler
option argument.

In the earlier case, reconfiguration with just holepunch state switched
may not trigger rebuild (config.h not changed). Also consistent with
most of other features.

Also removed HAVE_LIBJUICE guard from the udp_holepunch.h header -
no need to add config.h include for udp_holepunch.c.

Author: MartinPulec

configure.ac

@@ -1084,7 +1084,7 @@ if test "$libjuice_req" != no; then
         then
                 libjuice=yes
                 add_module holepunch src/utils/udp_holepunch.o "$LIBJUICE_LIB"
-                COMMON_FLAGS="$COMMON_FLAGS -DHAVE_LIBJUICE"
+                AC_DEFINE([HAVE_LIBJUICE], [1], [Linked with libjuice library])
         fi
 fi
 

src/utils/udp_holepunch.h

@@ -68,9 +68,7 @@ struct Holepunch_config{
         int stun_srv_port;
 };
 
-#ifdef HAVE_LIBJUICE
 bool punch_udp(struct Holepunch_config *c);
-#endif
 
 #ifdef __cplusplus
 } //extern "C"