Use the correct path to the include file.

--- libs/predef/test/build.jam.orig	2025-08-06 18:49:13 UTC
+++ libs/predef/test/build.jam
@@ -12,7 +12,7 @@ project
     :   requirements
         # Add explicit dependency since we don't have header scanner for
         # .m and .mm files.
-        <dependency>../include/boost/predef.h
+        <dependency>../../../boost/predef.h
     ;
 
 using testing ;