add comment about digital unix and interfaces.c warning with gcc

diff --git a/INSTALL b/INSTALL
index d4aac0d38512b7f7b33bf44e4562be4421ebe248..f0b78d1bfc081770ae91e608e9f6f16b9515c779 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -507,7 +507,15 @@ Digital UNIX:
     By default, sudo will use SIA (Security Integration Architecture)
     to validate a user.  If you want to use an alternate authentication
     method that does not go through SIA, you need to use the
-    --disable-sia option to configure.
+    --disable-sia option to configure.  If you use gcc to compile
+    you will get warnings when building interfaces.c.  These are
+    harmless but if they really bug you, you can edit
+    /usr/include/net/if.h around line 123, right after the comment:
+       /* forward decls for C++ */
+    change the line:
+       #ifdef __cplusplus
+    to:
+       #if defined(__cplusplus) || defined(__GNUC__)
 
 Linux:
     One person reported that he needed to run configure with