diff --git a/src/build/feature.jam b/src/build/feature.jam
index c656d8196..c4688e9c3 100644
--- a/src/build/feature.jam
+++ b/src/build/feature.jam
@@ -297,6 +297,7 @@ local rule validate-feature ( feature )
 local rule expand-subfeatures-aux ( 
     feature ? # The name of the feature, or empty if value corresponds to an implicit property
   : value     # The value of the feature.
+  : dont-validate ? # If set, no validation of value string will be done  
 )
 {
     if $(feature)
@@ -312,8 +313,11 @@ local rule expand-subfeatures-aux (
     {
         validate-feature $(feature) ;
     }
-    validate-value-string $(feature) $(value) ;
-
+    if ! $(dont-validate)
+    {        
+        validate-value-string $(feature) $(value) ;
+    }
+    
     local components = [ regex.split $(value) "-" ] ;
     
     # get the top-level feature's value
@@ -360,6 +364,7 @@ rule expand-subfeatures (
   properties * # property set with elements of the form
            # <feature>value-string or just value-string in the
            # case of implicit features.
+  : dont-validate ?
 )
 {
     local result ;
@@ -368,7 +373,7 @@ rule expand-subfeatures (
         # Don't expand subfeatures in subfeatures
         if ! [ MATCH "(:)" : $(p:G) ]
         {            
-            result += [ expand-subfeatures-aux $(p:G) : $(p:G=) ] ;
+            result += [ expand-subfeatures-aux $(p:G) : $(p:G=) : $(dont-validate) ] ;
         }
         else
         {
diff --git a/src/build/property.jam b/src/build/property.jam
index 0c7ff90be..72582a0d4 100644
--- a/src/build/property.jam
+++ b/src/build/property.jam
@@ -128,7 +128,7 @@ rule expand-subfeatures-in-conditions ( properties * )
     local result ;
     for local p in $(properties)
     {
-        local s = [ MATCH ([^:]*):(<.*) : $(p) ] ;        
+        local s = [ MATCH (.*):(<.*) : $(p) ] ;        
         if ! $(s)
         {
             result += $(p) ;
@@ -136,8 +136,26 @@ rule expand-subfeatures-in-conditions ( properties * )
         else
         {
             local condition = $(s[1]) ;
+            # Condition might include several elements
+            condition = [ regex.split $(condition) "," ] ;
             local value = $(s[2]) ;
-            local e = [ feature.expand-subfeatures $(condition) ] ;
+            local e ;
+            for local c in $(condition)
+            {           
+                if [ MATCH "^(<toolset>|<toolset->)" : $(c:G) ]
+                {
+                    # It common that condition includes a toolset which
+                    # was never defined, or mentiones subfeatures which
+                    # were never defined. In that case, validation will
+                    # only produce an spirious error, so don't validate.
+                    e += [ feature.expand-subfeatures $(c) : true ] ;
+                }               
+                else
+                {
+                    e += [ feature.expand-subfeatures $(c) ] ;
+                }                
+            }
+            
             if $(e) = $(condition)
             {
                 result += $(p) ;