Fix FTBFS due to the move of /usr/bin/python into a separate package

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

sratom.spec

@@ -3,7 +3,7 @@
 
 Name:       sratom
 Version:    0.6.0
-Release:    5%{?dist}
+Release:    6%{?dist}
 Summary:    A C library for serializing LV2 plugins
 
 Group:      System Environment/Libraries
@@ -11,6 +11,7 @@ License:    MIT
 URL:        http://drobilla.net/software/%{name}/
 Source0:    http://download.drobilla.net/%{name}-%{version}.tar.bz2
 BuildRequires:  python2
+BuildRequires:  python2-rpm-macros
 BuildRequires:  doxygen
 BuildRequires:  graphviz
 BuildRequires:  sord-devel >= 0.12.0
@@ -47,9 +48,8 @@ sed -i -e "s| '-ftest-coverage'\]|\
  '-ftest-coverage'\] + '%{optflags}'.split(' ')|" wscript
 
 %build
-export CFLAGS="%{optflags}" CXXFLAGS="%{optflags}"
+%set_build_flags
-export LDFLAGS="%{__global_ldflags}"
+%{__python2} waf configure -v \
-./waf configure -v \
     --prefix=%{_prefix} \
     --libdir=%{_libdir} \
     --mandir=%{_mandir} \
@@ -57,10 +57,10 @@ export LDFLAGS="%{__global_ldflags}"
     --docdir=%{_pkgdocdir} \
     --test \
     --docs 
-./waf build -v %{?_smp_mflags}
+%{__python2} waf build -v %{?_smp_mflags}
 
 %install
-DESTDIR=%{buildroot} ./waf install
+DESTDIR=%{buildroot} %{__python2} waf install
 chmod +x %{buildroot}%{_libdir}/lib%{name}-0.so.*
 install -pm 644 COPYING NEWS README %{buildroot}%{_pkgdocdir}
 
@@ -86,6 +86,9 @@ install -pm 644 COPYING NEWS README %{buildroot}%{_pkgdocdir}
 %{_mandir}/man3/*
 
 %changelog
+* Sun Jul 15 2018 Guido Aulisi <guido.aulisi@gmail.com> - 0.6.0-6
+- Fix FTBFS due to the move of /usr/bin/python into a separate package
+
 * Sat Jul 14 2018 Fedora Release Engineering <releng@fedoraproject.org> - 0.6.0-5
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_29_Mass_Rebuild