Consistently use buildroot macro

https://docs.fedoraproject.org/en-US/packaging-guidelines/#_using_buildroot_and_optflags_vs_rpm_build_root_and_rpm_opt_flags

glib2.spec

@@ -105,8 +105,8 @@ rm glib/pcre/*.[ch]
 # better reproducibility.
 # Also copy the timestamp for other .py files, because meson doesn't
 # do this, see https://github.com/mesonbuild/meson/issues/5027.
-touch -r gio/gdbus-2.0/codegen/config.py.in $RPM_BUILD_ROOT/%{_datadir}/glib-2.0/codegen/*.py
-chrpath --delete $RPM_BUILD_ROOT%{_libdir}/*.so
+touch -r gio/gdbus-2.0/codegen/config.py.in %{buildroot}%{_datadir}/glib-2.0/codegen/*.py
+chrpath --delete %{buildroot}%{_libdir}/*.so
 
 # Perform byte compilation manually to avoid issues with
 # irreproducibility of the default invalidation mode, see
@@ -115,12 +115,12 @@ chrpath --delete $RPM_BUILD_ROOT%{_libdir}/*.so
 export PYTHONHASHSEED=0
 %py_byte_compile %{__python3} %{buildroot}%{_datadir}
 
-mv  $RPM_BUILD_ROOT%{_bindir}/gio-querymodules $RPM_BUILD_ROOT%{_bindir}/gio-querymodules-%{__isa_bits}
+mv  %{buildroot}%{_bindir}/gio-querymodules %{buildroot}%{_bindir}/gio-querymodules-%{__isa_bits}
 
-touch $RPM_BUILD_ROOT%{_libdir}/gio/modules/giomodule.cache
+touch %{buildroot}%{_libdir}/gio/modules/giomodule.cache
 
 # bash-completion scripts need not be executable
-chmod 644 $RPM_BUILD_ROOT%{_datadir}/bash-completion/completions/*
+chmod 644 %{buildroot}%{_datadir}/bash-completion/completions/*
 
 %find_lang glib20
 
@@ -223,6 +223,7 @@ glib-compile-schemas %{_datadir}/glib-2.0/schemas &> /dev/null || :
 %changelog
 * Tue Jun 11 2019 David King <amigadave@amigadave.com> - 2.61.1-2
 - Fix CVE-2019-12450 (#1719142)
+- Consistently use buildroot macro
 
 * Fri May 24 2019 Kalev Lember <klember@redhat.com> - 2.61.1-1
 - Update to 2.61.1