[Boost-build] Fix for bbv1 path-global attached

From: Roland Schwarz (roland.schwarz_at_[hidden])
Date: 2006-07-17 06:55:10

I have already reported, that the path-global does not work when used 
from external projects.

Since bbv1 is almost about to be retired my fix might not be of too much 
interest. But since I found a fix I post it here, in case anyone else 
might need it.

The fix is as noninvasive as possible and will only be triggered when 
referring to external projects. This way the build of the boost library 
is not affected in any way.

Basically it will allow to put
path-global MYPATH : ../../foo/bar
variables into Jamrules files of external projects. More important, 
however is that the construct
path-global BOOST_ROOT : ../../boost
will correctly work when put in the Jamrules of an external project.

The fix modifies the code path for external projects in the project rule 
within allyourbase.jam

rule project ( name : location ? )
{
     if ! $(location)
     {
         gPROJECT($(name)) = $(gPROJECT($(PROJECT))) ;
         PROJECT($(gPROJECT($(name)))) = $(name) ;
         PROJECT = $(name) ;
     }
     else
     {
         gPROJECT($(name)) = [ root-paths $(location) :
             [ root-paths $($(gTOP)) : [ PWD ] ] ] ;
# fix starts here
         local val ;
         for val in $(gPATH_GLOBALS) {
         gPATH_GLOBAL_VALUE($(val)) =
             [ root-paths  $(gPATH_GLOBAL_VALUE($(val))) :
                 [ root-paths $($(gTOP)) : [ PWD ]  ]
             ] ;
         }
# fix ends here
         local [ protect-subproject ] ;
         enter-subproject @$(name) ; 

     }
}

Best regards,
Roland