support both EL7 and Fedora

Use %cmake3 macro and %{_libdir}/cmake as dependency because
there's no cmake3-filesystem package in EL7. Also, fix unowned
%{_libdir}/cmake/ebml directory.

libebml.spec

@@ -7,7 +7,7 @@ Group:      System Environment/Libraries
 URL:        https://www.matroska.org/
 Source:     https://dl.matroska.org/downloads/%{name}/%{name}-%{version}.tar.xz
 Patch0:     %{name}-use-system-utf8cpp.patch
-BuildRequires: cmake
+BuildRequires: cmake3
 BuildRequires: gcc-c++
 BuildRequires: utf8cpp-devel
 
@@ -21,7 +21,7 @@ pendant to XML.
 Summary:    Development files for the Extensible Binary Meta Language library
 Group:      Development/Libraries
 Requires:   %{name}%{?_isa} = %{version}-%{release}
-Requires:   cmake-filesystem
+Requires:   %{_libdir}/cmake
 Requires:   pkgconfig
 
 %description devel
@@ -40,7 +40,7 @@ rm -r src/lib/utf8-cpp
 
 
 %build
-%cmake
+%cmake3 .
 make %{?_smp_mflags}
 
 
@@ -60,6 +60,7 @@ make %{?_smp_mflags}
 %{_includedir}/ebml/
 %{_libdir}/%{name}.so
 %{_libdir}/pkgconfig/%{name}.pc
+%dir %{_libdir}/cmake/ebml
 %{_libdir}/cmake/ebml/EbmlConfig.cmake
 %{_libdir}/cmake/ebml/EbmlConfigVersion.cmake
 %{_libdir}/cmake/ebml/EbmlTargets-noconfig.cmake
@@ -70,6 +71,7 @@ make %{?_smp_mflags}
 * Fri Jun 07 2019 Dominik Mierzejewski <rpm@greysector.net> - 1.3.7-1
 - update to 1.3.7
 - unbundle utf8cpp
+- fix unowned %%{_libdir}/cmake/ebml directory
 
 * Mon Jul 23 2018 Dominik Mierzejewski <rpm@greysector.net> - 1.3.6-1
 - update to 1.3.6 (#1570224)