Fix build system error when Python is not configured, without preventing the BPL target from being declared. Instead the target is now unbuildable, and will be skipped when Python is not configured.

grafikrobot · grafikrobot · commit f0055186869e · 2007-10-18T16:11:41.000Z
[SVN r40156]
diff --git a/build/Jamfile.v2 b/build/Jamfile.v2
@@ -12,6 +12,9 @@ project boost/python
   : source-location ../src
   ;
 
+rule cond ( test ? : yes * : no * ) { if $(test) { return $(yes) ; } else { return $(no) ; } }
+rule unless ( test ? : yes * : no * ) { if ! $(test) { return $(yes) ; } else { return $(no) ; } }
+
 lib boost_python
     : # sources
     numeric.cpp
@@ -60,7 +63,12 @@ lib boost_python
         # python_for_extensions is a target defined by Boost.Build to
         # provide the Python include paths, and on Windows, the Python
         # import library, as usage requirements.
-        <library>/python//python_for_extensions
+        [ cond [ python.configured ] : <library>/python//python_for_extensions ]
+        
+        # we prevent building when there is no python available
+        # as it's not possible anyway, and to cause dependents to
+        # fail to build
+        [ unless [ python.configured ] : <build>no ]
       
     :   # default build
         <link>shared
