diff --git a/xtide.spec b/xtide.spec
index cdcb24e..6d21f1c 100644
--- a/xtide.spec
+++ b/xtide.spec
@@ -8,7 +8,7 @@
 %endif
 
 
-%define          fedorarel 5
+%define          fedorarel 6
 
 
 %define          rel        %{?betatag:0.}%{fedorarel}%{?betatag:.%(echo %betatag | sed -e 's|-||g')}
@@ -41,6 +41,7 @@ Patch0:          xtide-2.12.1-rcscript-pidfile.patch
 License:         GPLv3+
 Group:           Applications/Engineering
 
+BuildRequires:   gcc-c++
 BuildRequires:   libXaw-devel
 BuildRequires:   libXext-devel
 BuildRequires:   libpng-devel
@@ -412,6 +413,9 @@ exit 0
 %{_datadir}/man/man8/xttpd.8*
 
 %changelog
+* Mon Jul 15 2018 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.1-6
+- F-29: mass rebuild
+
 * Thu Feb 15 2018 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.15.1-5
 - harmonics data update (20180101)