diff --git a/ninja-build.spec b/ninja-build.spec
index 4416b47..aec45b8 100644
--- a/ninja-build.spec
+++ b/ninja-build.spec
@@ -37,7 +37,15 @@ fast as possible.
 %autosetup -n ninja-%{version} -p1
 
 %build
-CFLAGS="%{optflags}" LDFLAGS="%{?__global_ldflags}" \
+%if 0%{?set_build_flags:1}
+%{set_build_flags}
+%else
+CFLAGS="${CFLAGS:-%optflags}" ; export CFLAGS
+CXXFLAGS="${CXXFLAGS:-%optflags}" ; export CXXFLAGS
+FFLAGS="${FFLAGS:-%optflags%{?_fmoddir: -I%_fmoddir}}" ; export FFLAGS
+FCFLAGS="${FCFLAGS:-%optflags%{?_fmoddir: -I%_fmoddir}}" ; export FCFLAGS
+%{?__global_ldflags:LDFLAGS="${LDFLAGS:-%__global_ldflags}" ; export LDFLAGS ;}
+%endif
 %if 0%{?rhel} && 0%{?rhel} <= 7
 %{__python2} \
 %else
@@ -92,6 +100,7 @@ ln -s ninja %{buildroot}%{_bindir}/ninja-build
 %changelog
 * Wed Feb 05 2020 Björn Esser <besser82@fedoraproject.org> - 1.9.0-5
 - Add conditional for bootstrapping new architectures
+- Use %%set_build_flags macro to export buildflags, if available
 
 * Wed Jan 29 2020 Fedora Release Engineering <releng@fedoraproject.org> - 1.9.0-4
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_32_Mass_Rebuild