during ./configure i get

checking for glib-2.0 >= 2.5.7 gobject-2.0 gmodule-no-export-2.0... Package gmodule-no-export-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gmodule-no-export-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gmodule-no-export-2.0' found
configure: error:
*** Glib 2.5.7 or better is required. The latest version of
*** Glib is always available from ftp://ftp.gtk.org/.

but an echo $PKG_CONFIG_PATH will print /usr/local/src/glib-2.6.3 and that dir contains
gmodule-no-export-2.0.pc
pkg-config --modversion glib-2.0 returns 2.6.3, so why doesn't it detect gmodule-no-export-2.0.pc?

and also pkgtool doesn't have glib-2.6.3 listed... what'd i do this time?

your using the wrong directory for pkg-config. depending on where you installed glib ( i'll assume /usr/local judging by your post, which is usually wrong if your distro shipped with glib and the rest of the gnome libs):

export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:$PKG_CONFIG_PATH

will point pkg-config to the correct file.