RFA: PATCH to gengtype to avoid putting tree_node support in front end objects

[Jason Merrill <jason at redhat dot com>]

Currently, the way gengtype works it scans the list of source files
with front end files at the end, and pushes data structures onto a
stack.  It then processes the stack in LIFO order, so that data
structures from front ends are handled first.  As a result, if a GTY
data structure in a front end depends on tree_node, gengtype happily
puts gt_ggc_mx(tree_node*&) in a front end file, leading to link
errors on all other front ends.

This patch avoids this problem by appending to the list of data
structures so that they are processed in FIFO order, and so tree_node
gets handled in gtype-desc.o.

Tested x86_64-pc-linux-gnu, OK for trunk?

Attachment: gtype.diff
Description: Text document