Merge from ast-arena. This reduces the code in Python/ast.c by ~300 lines,
simplifies a lot of error handling code, and fixes many memory leaks.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index bae4250..ab01deb 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -254,6 +254,7 @@
Python/modsupport.o \
Python/mystrtoul.o \
Python/mysnprintf.o \
+ Python/pyarena.o \
Python/pyfpe.o \
Python/pystate.o \
Python/pythonrun.o \
@@ -520,6 +521,7 @@
Include/object.h \
Include/objimpl.h \
Include/patchlevel.h \
+ Include/pyarena.h \
Include/pydebug.h \
Include/pyerrors.h \
Include/pyfpe.h \