diff --git a/arj.spec b/arj.spec
index 9b8183c..992aa0e 100644
--- a/arj.spec
+++ b/arj.spec
@@ -56,13 +56,15 @@ popd
 
 %build
 pushd gnu
-  %if 0%{?rhel} <= 6
-  # Workaround for "Patch not found" (https://gnats.netbsd.org/36919)
-  export CFLAGS="$CFLAGS -fno-unit-at-a-time"
-  %endif
-  %if 0%{?rhel} == 6
-  # Workaround for "machine `x86_64-redhat' not recognized" from config.sub
-  cp -pf /usr/lib/rpm/redhat/config.{guess,sub} .
+  %if 0%{?rhel}
+    %if 0%{?rhel} <= 6
+    # Workaround for "Patch not found" (https://gnats.netbsd.org/36919)
+    export CFLAGS="$RPM_OPT_FLAGS -fno-unit-at-a-time"
+    %endif
+    %if 0%{?rhel} == 6
+    # Workaround for "machine `x86_64-redhat' not recognized" from config.sub
+    cp -pf /usr/lib/rpm/redhat/config.{guess,sub} .
+    %endif
   %endif
   %configure
 popd