broken: pkg-config and $includedir/gnome-2.0

[jacob berkman <jacob ximian com>]

i've found some brokenness in how pkg-config handles having multiple
versions of packages in $PKG_CONFIG_PATH.  i apologize for the lack of
brevity in this mail, but the problem is a little complex.

i have libgnomecanvas-2.0 and libgnome-2.0 (packages which aren't
dependant on each other, and only actually both depend on glib2-2.0)
installed from packages in /usr.  i also have a /gnome2 where i can work
on things without trashing my system.  i have libgnomecanvas-2.0
installed there, also.

some environment flags i have set:

declare -x GNOME_PATH="/gnome2:/usr"
declare -x LD_LIBRARY_PATH="/gnome2/lib"
declare -x PKG_CONFIG_PATH="/gnome2/lib/pkgconfig:/usr/lib/pkgconfig"

from these things, everything should be looking in /gnome2 first.

so, with pkg-config each package should be putting its include files in
a subdirectory of a unique-per-package-"platform"-version directory
(glib uses $includedir/glib-2.0).  however, gnome sublibraries are all
sharing $includedir/gnome-2.0.  this breaks in my above scenario.

if i do "pkg-config --cflags libgnome-2.0 libgnomecanvas-2.0", libgnome
will add -I/usr/include/gnome-2.0 before the canvas adds
-I/gnome2/include/gnome-2.0.  this results in the canvas headers from
/usr/include/gnome-2.0 being used.

however, if i do "pkg-config --cflags libgnomecanvas-2.0 libgnome-2.0",
it will work how i expect.  this might be easier to understand with:

jacob wet-pants:jacob G2$ pkg-config --libs-only-L libgnomecanvas-2.0 libgnome-2.0
-L/gnome/lib -L/usr/lib -L/usr/X11R6/lib  
jacob wet-pants:jacob G2$ pkg-config --libs-only-L libgnome-2.0 libgnomecanvas-2.0
-L/usr/lib -L/gnome/lib -L/usr/X11R6/lib  

at link time, libgnomecanvas would get pulled from /usr/lib but at run
time (due to LD_LIBRARY_PATH) it will link against the one in
/gnome2/lib!

the problem is that pkg-config is doing:

    for directory in searchpath:
        for file in directory:
    	add_to_hash
    
    for pkg in pkglist:
        if pkg is in hash
    	load_flags
        else
    	error
    
while i think it should be doing something more like:

    for pkg in pkglist:
        add_to_hash
    
    for directory in searchpath:
        for file in directory:
    	if file is in hash
    	   load flags
    	   mark pkg as found
    
    for pkg in pkglist
        if pkg isn't found
    	error

so gnome maintainers, anyone have a problem with me fixing the include
dirs not to be $includedir/gnome-2.0, but use $includedir/$PACKAGE-2.0 ?

pkg-config guys, thoughts?

hopefully this was somewhat understandable.

jacob
-- 
"Beat mixing is 10000 times more fun than even video games."
	-- bt