Add ABI dump script (#94135)

Author: pablogsal

.github/workflows/regen-abidump.sh

@@ -0,0 +1,8 @@
+set -ex
+
+export DEBIAN_FRONTEND=noninteractive
+./.github/workflows/posix-deps-apt.sh
+apt-get install -yq abigail-tools python3
+export CFLAGS="-g3 -O0"
+./configure --enable-shared && make
+make regen-abidump

.gitignore

@@ -150,3 +150,6 @@ Python/frozen_modules/MANIFEST
 # Ignore ./python binary on Unix but still look into ./Python/ directory.
 /python
 !/Python/
+
+# main branch only: ABI files are not checked/maintained
+Doc/data/python*.abi

Makefile.pre.in

@@ -1204,7 +1204,7 @@ regen-global-objects: $(srcdir)/Tools/scripts/generate_global_objects.py
 regen-abidump: all
 	@$(MKDIR_P) $(srcdir)/Doc/data/
 	abidw "libpython$(LDVERSION).so" --no-architecture --out-file $(srcdir)/Doc/data/python$(LDVERSION).abi.new
-	@$(UPDATE_FILE) $(srcdir)/Doc/data/python$(LDVERSION).abi $(srcdir)/Doc/data/python$(LDVERSION).abi.new
+	@$(UPDATE_FILE) --create $(srcdir)/Doc/data/python$(LDVERSION).abi $(srcdir)/Doc/data/python$(LDVERSION).abi.new
 
 check-abidump: all
 	abidiff $(srcdir)/Doc/data/python$(LDVERSION).abi "libpython$(LDVERSION).so" --drop-private-types --no-architecture --no-added-syms