bjam HDRS rule in python tutorial compilation

[ljo_]

When I set HDRS to a value it has no effect.
It always produces the value -I"bin/boost" or
-I"bin/tutorial".
When checked with "-d+7" you can see that the original
value is overwritten halfway in the process.
As far as I can see nobody uses HDRS in a Boost Jamfile.

[david_abrahams]

Logged In: YES 
user_id=52572

Why do you think that's a problem?  Did something in the
documentation for Boost.Python lead you to believe that the
environment variable HDRS would be used for anything?

[ljo_]

Logged In: YES 
user_id=1335326

Searching in the bjam documentation for a means to set my
own extra include files, I found this in
"http://www.boost.org/tools/build/jam_src/Jambase.html":

Jambase Rules
...
HDRS 
Directories to be searched for header files. This is used by
the Object rule to: set up search paths for finding files
returned by header scans add -I flags on compile commands 

When I tried to set it in the Jamfile with a line:
    HDRS = path ;

It did not do what I expected (An extra '-I path' in the gcc
command). Did I misunderstand the rule (or all of bjam)?

[david_abrahams]

Logged In: YES 
user_id=52572

This is not a bug.  To set your own extra include files,
please add <include>some/path to the BUILD variable on your
bjam command-line.  For example,

  bjam "-sBUILD=<include>/usr/local/foobar/include"  ...