Use make macros

https://fedoraproject.org/wiki/Changes/UseMakeBuildInstallMacro

libidn.spec

@@ -111,22 +111,22 @@ sed -i 's|^runpath_var=LD_RUN_PATH|runpath_var=DIE_RPATH_DIE|g' libtool
 # without RPATH this needs to be set for idn executed by help2man
 export LD_LIBRARY_PATH=$(pwd)/lib/.libs
 
-make %{?_smp_mflags} V=1
+%make_build
 
 %check
 # without RPATH this needs to be set to test the compiled library
 export LD_LIBRARY_PATH=$(pwd)/lib/.libs
-make %{?_smp_mflags} -C tests check VALGRIND=env
+%make_build -C tests check VALGRIND=env
 
 %install
-make install DESTDIR=$RPM_BUILD_ROOT pkgconfigdir=%{_libdir}/pkgconfig \
+%make_install pkgconfigdir=%{_libdir}/pkgconfig \
 %if %{with libidn_enables_java}
     libidn_jardir=%{_javadir} \
 %endif
     ;
 
 # provide more examples
-make %{?_smp_mflags} -C examples distclean
+%make_build -C examples distclean
 
 # clean up docs
 find doc -name "Makefile*" | xargs rm