building gtk: undefined symbols are really macros

[Charles Smith <cts private yahoo com>]

If glib defines g_string_append_uri_escaped() as a macro, why is it showing up undefined in glib/libgio-2.0.so?

In building gtk+-2.18.3, I get the following message (along with many similar messages):
  /opt/gtk/lib/libgio-2.0.so: undefined reference to `g_string_append_uri_escaped'

I got the clue from the net that this is defined in glib (glib-2.22.2, in my case).  But a bit of digging reveals that these symbols are implemented as macros inside glib/.  The gio library seems not to reference them, though - I can't find an include of galias.h in that subdirectory, and compiling with the -E option yields no galias.h file included.