diff --git a/net-misc/muscle/muscle-6.00.recipe b/net-misc/muscle/muscle-6.00.recipe
index 4fd593b09..5f29eb67f 100644
--- a/net-misc/muscle/muscle-6.00.recipe
+++ b/net-misc/muscle/muscle-6.00.recipe
@@ -18,8 +18,13 @@ SRC_URI="https://public.msli.com/lcs/muscle/muscle6.00.zip"
 CHECKSUM_SHA256="b12abe12b5cc4aa93126f86ae07a4bcd02ee8d89d692789435debd5becc53437"
 REVISION="1"
 
-ARCHITECTURES="!x86_gcc2 x86 ?x86_64"
-SECONDARY_ARCHITECTURES="!x86_gcc2 x86"
+ARCHITECTURES="x86 ?x86_64"
+if [ $effectiveTargetArchitecture != x86_gcc2 ]; then
+	# x86_gcc2 is fine as primary target architecture as long as we're building
+	# for a different secondary architecture.
+	ARCHITECTURES="$ARCHITECTURES x86_gcc2"
+fi
+SECONDARY_ARCHITECTURES="x86"
 
 PROVIDES="
 	muscle = $portVersion