autoconf: Fix thinko when checking freebsd CPU types
diff --git a/configure.ac b/configure.ac
index e67cd54..a7707f8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -795,7 +795,7 @@
     ;;
 freebsd*)
     PIC_FLAGS="-fPIC"
-    case "$host_os" in
+    case "$host_cpu" in
     i*86)
         PIC_FLAGS=""
         if test "x$enable_asm" = xyes; then