avahi: fix build on some distributions

This seems to happen only on some distributions (Void, Arch):

    /usr/lib/libgcc_s.so.1: file not recognized: file format not recognized
    collect2: error: ld returned 1 exit status
    libtool:   error: error: relink 'libdns_sd.la' with the above command before installing it

Signed-off-by: Michal Vasilek <michal.vasilek@nic.cz>

libs/avahi/Makefile

@@ -21,6 +21,7 @@ PKG_LICENSE:=LGPL-2.1-or-later
 PKG_LICENSE_FILES:=LICENSE
 PKG_CPE_ID:=cpe:/a:avahi:avahi
 
+PKG_FIXUP:=autoreconf
 PKG_INSTALL:=1
 PKG_BUILD_PARALLEL:=1