Changed the #error to a #warning when checking gcc versions, and
noted the minimum recommended version in the message.
diff --git a/PC/config.h b/PC/config.h
index 7081551..6a1e4c1 100644
--- a/PC/config.h
+++ b/PC/config.h
@@ -31,7 +31,7 @@
    compiler don't exhibit this bug.
 */
 #if (__GNUC__==2) && (__GNUC_MINOR__<=91)
-#error "Please use an up-to-date version of gcc"
+#warning "Please use an up-to-date version of gcc! (>2.91 recommended)"
 #endif
 
 /*