Index: libs/predef/test/build.jam
===================================================================
--- libs/predef/test/build.jam	(revision 85888)
+++ libs/predef/test/build.jam	(working copy)
@@ -4,19 +4,34 @@
 # (See accompanying file LICENSE_1_0.txt or copy at
 # http://www.boost.org/LICENSE_1_0.txt)
 
+local predef-include-root ;
+local predef-dependency ;
+
+# When using modular layout, header files are not present in $root/boost
+# unlink links are created, therefore instead of direct dependency on
+# a header, we need to use dependency on metatarget.
 if $(BOOST_PREDEF_ROOT)
 {
-    path-constant BOOST_PREDEF_INCLUDE_ROOT : $(BOOST_PREDEF_ROOT)/include ;
+    predef-include-root = $(BOOST_PREDEF_ROOT)/include ;
+    predef-dependency = $(predef-include-root)/boost/predef.h ;
 }
+else if $(BOOST_MODULARLAYOUT)
+{
+    predef-include-root = $(BOOST_ROOT)/include ;
+    predef-dependency = /boost//predef-headers ;
+}
 else
 {
-    path-constant BOOST_PREDEF_INCLUDE_ROOT : $(BOOST_ROOT) ;
+   predef-include-root = $(BOOST_ROOT) ;
+   predef-dependency = $(predef-include-root)/boost/predef.h ;         
 }
 
 project test
     :   requirements
-        <include>$(BOOST_PREDEF_INCLUDE_ROOT)
-        <dependency>$(BOOST_PREDEF_INCLUDE_ROOT)/boost/predef.h
+        <include>$(predef-include-root)
+        # Add explicit dependency since we don't have header scanner for
+        # .m and .mm files.
+        <dependency>$(predef-dependency)
     ;
 
 using testing ;
Index: Jamroot
===================================================================
--- Jamroot	(revision 85889)
+++ Jamroot	(working copy)
@@ -143,6 +143,7 @@
 for dir in $(all-headers)
 {
     link-directory $(dir)-headers : libs/$(dir)/include/boost : <location>. ;
+    explicit $(dir)-headers ;
 }
 
 local numeric-headers =
@@ -151,9 +152,13 @@
 for dir in $(numeric-headers)
 {
     link-directory numeric-$(dir)-headers : libs/numeric/$(dir)/include/boost : <location>. ;
+    explicit numeric-$(dir)-headers ;
 }
 
-BOOST_MODULARLAYOUT = $(all-headers) $(numeric-headers) ;
+if $(all-headers)
+{
+    constant BOOST_MODULARLAYOUT : $(all-headers) $(numeric-headers) ;
+}
 if $(BOOST_MODULARLAYOUT)
 {
     echo modularized layout build ;