diff --git a/python-rpi-gpio.spec b/python-rpi-gpio.spec
index 455890c..2661410 100644
--- a/python-rpi-gpio.spec
+++ b/python-rpi-gpio.spec
@@ -32,7 +32,8 @@ Python 3 library for GPIO access on a Raspberry Pi.
 %autosetup -n %{srcname}-%{version}
 
 %build
-%py3_build CFLAGS="${RPM_OPT_FLAGS} -fcommon"
+CFLAGS="${RPM_OPT_FLAGS} -fcommon"
+%py3_build
 
 %install
 %py3_install