Install perl modules into /usr, not /usr/local.

$ perl -MConfig -e 'print "$Config{archlib}\n"'
/usr/lib64/perl5/5.24.3/x86_64-linux
$ perl -MConfig -e 'print "$Config{sitearch}\n"'
/usr/local/lib64/perl5/5.24.3/x86_64-linux
--- a/waflib/Tools/perl.py
+++ b/waflib/Tools/perl.py
@@ -75,7 +75,7 @@ def check_perl_ext_devel(self):
 	env.EXTUTILS_TYPEMAP=cfg_lst('$Config{privlib}/ExtUtils/typemap')
 	env.XSUBPP=find_xsubpp()
 	if not getattr(Options.options,'perlarchdir',None):
-		env.ARCHDIR_PERL=cfg_str('$Config{sitearch}')
+		env.ARCHDIR_PERL=cfg_str('$Config{archlib}')
 	else:
 		env.ARCHDIR_PERL=getattr(Options.options,'perlarchdir')
 	env.perlext_PATTERN='%s.'+cfg_str('$Config{dlext}')