diff --git a/arj.spec b/arj.spec
index 3e7f0d6..1840b03 100644
--- a/arj.spec
+++ b/arj.spec
@@ -56,6 +56,14 @@ 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} .
+  %endif
   %configure
 popd