Reimplement addbuilddir() in C inside getpath.c, so as to execute it
at interpreter startup before importing any non-builtin modules.
Should fix #9589.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 279e8d7..09d80d4 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1213,6 +1213,7 @@
Modules/Setup Modules/Setup.local Modules/Setup.config \
Misc/python.pc
-rm -f python*-gdb.py
+ -rm -f pybuilddir.txt
find $(srcdir) '(' -name '*.fdc' -o -name '*~' \
-o -name '[@,#]*' -o -name '*.old' \
-o -name '*.orig' -o -name '*.rej' \