BR c++ and disable tests on el6

cmark.spec

@@ -1,6 +1,12 @@
+%if %{defined rhel}
+%if %{rhel} < 7
+%global disable_tests -D CMARK_TESTS=OFF
+%endif
+%endif
+
 Name:           cmark
 Version:        0.23.0
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        CommonMark parsing and rendering
 
 License:        BSD and MIT
@@ -9,6 +15,7 @@ Source0:        https://github.com/jgm/cmark/archive/%{version}.tar.gz#/%{name}-
 Patch1:         cmark-lib64.patch
 
 BuildRequires:  cmake
+BuildRequires:  gcc-c++
 
 %description
 `cmark` is the C reference implementation of CommonMark,
@@ -47,7 +54,7 @@ This package provides the cmark library.
 %build
 mkdir build
 cd build
-%cmake ..
+%cmake .. %{?disable_tests}
 make %{?_smp_mflags}
 
 
@@ -91,6 +98,10 @@ ctest -V %{?_smp_mflags}
 
 
 %changelog
+* Thu Jan 28 2016 Jens Petersen <petersen@redhat.com> - 0.23.0-4
+- BR c++ explicitly
+- disable tests for EPEL6 since no python3
+
 * Mon Jan 25 2016 Jens Petersen <petersen@redhat.com> - 0.23.0-3
 - include license in lib (#1266429)