Re: [Module::Build] [PATCH] ExtUtils::CBuilder - process defines & extra_compiler_flags

Ken Williams wrote:
> I've applied it, and then I'm going to move the 
> actual formatting of the -Dfoo=bar arguments (and other platform 
> equivalents) to a new arg_defines() method, just like arg_object_file(), 
> arg_nolink(), and the like.
> 
> Also, would you care to write a documentation patch mentioning the new 
> 'defines' parameter?

Sure, but in writing it I realized the need to alter the behavior 
somewhat. In particular an array should be used instead of a hash to 
preserve order of definition, and C<undef> as a value should either be 
an error or used as described in the doc patch below to undefine macros. 
I'll patch CBuilder to follow the behavior described if you can send me 
the changes you mentioned above.

Note, given the C program:

#include <stdio.h>
main(){printf("%s\n",MACRO);}

The commands:

gcc -DMACRO=\"foo\" test.c
gcc -DFOO=\"foo\" -DMACRO=FOO test.c

both output the string "foo\n". The second command defines a macro and 
then uses it in a subsequent macro, so order can be important.

But, I'm not sure how to implement the reference to a previously defined