Failed to compile after dabd71bb2bf with gcc 4.8.3

[Masanari Iida]

After following commit merged into main tree,
it started to fail compiling systemtap with gcc 4.8.3 (on Fedora 20, x86_64),

commit dabd71bb2bfae4154229af4576771c788da0604a
Author: Mark Wielaard <mjw@redhat.com>
Date:   Sun Jan 24 20:59:13 2016 +0100

    Use -Wextra. Fix some warnings.

-- Error messages --

  CXX      stap-rpm_finder.o
rpm_finder.cxx:205:1: error: unused parameter ‘sess’ [-Werror=unused-parameter]
 missing_rpm_list_print (systemtap_session &sess, const char* rpm_type)
 ^
rpm_finder.cxx:205:1: error: unused parameter ‘rpm_type’
[-Werror=unused-parameter]
rpm_finder.cxx:232:1: error: unused parameter ‘sess’ [-Werror=unused-parameter]
 find_debug_rpms (systemtap_session &sess, const char * filename)
 ^
rpm_finder.cxx:232:1: error: unused parameter ‘filename’
[-Werror=unused-parameter]
rpm_finder.cxx:242:5: error: unused parameter ‘sess’ [-Werror=unused-parameter]
 int find_devel_rpms(systemtap_session &sess, const char * filename)
     ^
rpm_finder.cxx:242:5: error: unused parameter ‘filename’
[-Werror=unused-parameter]
cc1plus: all warnings being treated as errors
make[2]: *** [stap-rpm_finder.o] Error 1

Regards,
Masanari