Index: convert.jam
===================================================================
--- convert.jam	(revision 77789)
+++ convert.jam	(working copy)
@@ -9,7 +9,7 @@
 #
 # For example:
 #
-#   convert objects obj : a.cpp b.cpp ;
+#   convert objects obj : a.cpp b.cpp c.c d.s ;
 #
 
 import targets ;
@@ -29,19 +29,61 @@
 
     rule construct ( name : source-targets * : property-set )
     {
-        local r = [ generators.construct $(self.project) : $(self.type)
-          : [ property-set.create [ $(property-set).raw ] # [ feature.expand
-              <main-target-type>$(self.type) ]
-          # ]
-            : $(source-targets) ] ;
-        if ! $(r)
+        local usage-requirements ;
+        local result ;
+        while $(source-targets)
         {
-            errors.error "unable to construct" [ full-name ] ;
+            local stype ;
+            local s-one-type ;
+            local s-other-types ;
+            for s in $(source-targets)
+            {
+                if ! $(stype)
+                {
+                    stype = [ $(s).type ] ;
+                }
+                if [ $(s).type ] = $(stype)
+                {
+                    s-one-type += $(s) ;
+                } else
+                {
+                    s-other-types += $(s) ;
+                }
+            }
+            source-targets = $(s-other-types) ;
+            local r = [ generators.construct $(self.project) : $(self.type)
+                        : [ property-set.create [ $(property-set).raw ] # [ feature.expand
+                                                <main-target-type>$(self.type) ]
+            # ]
+                        : $(s-one-type) : true ] ;
+            if ! $(r)
+            {
+                errors.error "unable to construct" [ full-name ] ;
+            }
+            if [ class.is-a $(r[1]) : property-set ]
+            {
+                if $(usage-requirements)
+                   && $(usage-requirements) != $(r[1])
+                {
+                    errors.error "too many usage-requirements by construct" [ full-name ] "\n"
+                                 [ $(usage-requirements).raw ] "\n"
+                                 [ $(r[1]).raw ] ;
+                } else if ! $(usage-requirements)
+                {
+                    usage-requirements = $(r[1]) ;
+                }
+                result = [ sequence.merge $(result) : $(r[2-]) ] ;
+            } else
+            {
+                result = [ sequence.merge $(result) : $(r) ] ;
+            }
         }
-
-        return $(r) ;
+        if ! $(usage-requirements)
+        {
+            usage-requirements = [ property-set.empty ] ;
+        }
+        return $(usage-requirements) $(result) ;
     }
-
 }
 
 rule convert ( name type : sources * : requirements * : default-build *