diff --git a/rubygem-rkerberos.spec b/rubygem-rkerberos.spec
index bece613..cc81cd3 100644
--- a/rubygem-rkerberos.spec
+++ b/rubygem-rkerberos.spec
@@ -14,7 +14,7 @@ Summary: A Ruby interface for the the Kerberos library
 Name: %{?scl_prefix}rubygem-%{gem_name}
 
 Version: 0.1.5
-Release: 2%{?dist}
+Release: 3%{?dist}
 Group: Development/Languages
 License: Artistic 2.0
 URL: http://github.com/domcleal/rkerberos
@@ -62,15 +62,17 @@ gem unpack %{SOURCE0}
 
 %setup -q -D -T -n  %{gem_name}-%{version}
 
-# Workaround for the following error on ppc{,64)
+# Workaround for the following error on ppc64{,le)
 #In file included from /usr/include/gssrpc/rpc.h:46:0,
 #                 from /usr/include/kadm5/admin.h:45,
 #                 from ./rkerberos.h:9,
 #                 from ccache.c:1:
 #/usr/include/gssrpc/xdr.h:123:38: error: unknown type name 'caddr_t'
 #   bool_t (*x_getbytes)(struct XDR *, caddr_t, u_int);
+#
+# Also see: https://bugzilla.redhat.com/show_bug.cgi?id=1412274
 sed -i \
-	-e '\@CFLAGS@s|-pedantic|\0 -D_DEFAULT_SOURCE|' \
+	-e '\@CFLAGS@s|-std=c99||' \
 	ext/rkerberos/extconf.rb
 
 %{?scl:scl enable %{scl} "}
@@ -141,6 +143,10 @@ popd
 
 
 %changelog
+* Wed Jan 25 2017 Mamoru TASAKA <mtasaka@fedoraproject.org> - 0.1.5-3
+- Use GNU extension for compilar flag to avoid build failure on
+  ppc64{,le} wrt kerberos header (bug 1412274)
+
 * Thu Jan 12 2017 Mamoru TASAKA <mtasaka@fedoraproject.org> - 0.1.5-2
 - F-26: rebuild for ruby24
 - add -D_DEFAULT_SOURCE for now