Index: libs/iostreams/build/Jamfile.v2
===================================================================
--- libs/iostreams/build/Jamfile.v2	(revision 86799)
+++ libs/iostreams/build/Jamfile.v2	(working copy)
@@ -21,6 +21,7 @@
 import os ;
 import path ;
 import ac ;
+import print ;
 local debug = [ MATCH (--debug-configuration) : [ modules.peek : ARGV ] ] ;
 
 for local v in NO_COMPRESSION 
@@ -144,11 +145,43 @@
     }        
 }
 
+if [ os.name ] = NT
+{
+    rule read-file ( file )
+    {
+        return [ SPLIT_BY_CHARACTERS [ SHELL "type \"$(file:G=)\" 2>nul" ] : "\n" ] ;
+    }
+}
+else
+{
+    rule read-file ( file )
+    {
+        return [ SPLIT_BY_CHARACTERS [ SHELL "cat \"$(file:G=)\" 2>/dev/null" ]  : "\n" ] ;
+    }
+}
 
+rule make-bz2-def-file ( target : source : properties * )
+{
+    print.output $(target) ;
+    for local line in [ read-file $(source) ]
+    {
+        if ! [ MATCH "(LIBRARY[ \t]+LIBBZ2)" : $(line) ]
+        {
+            print.text $(line) : yes ;
+        }
+    }
+}
+
+if $(BZIP2_SOURCE)
+{
+    make bz2.def : $(BZIP2_SOURCE)/libbz2.def : @make-bz2-def-file ;
+    bz2-def-file = bz2.def ;
+}
+
 local sources = file_descriptor.cpp mapped_file.cpp ;
 local bz2 = [ create-library bzip2 : libbz2 bz2 : 
     blocksort bzlib compress crctable decompress huffman randtable :
-    <link>shared:<def-file>$(BZIP2_SOURCE)/libbz2.def ] ;
+    <link>shared:<def-file>$(bz2-def-file) ] ;
 
 if $(bz2)
 {