Added new merging script and updated build scripts accordingly

Recent commits in the PG17 code added additional API changes,
making the "single src directory with ifdefs" approach inpractical.

This commit adds a new python based script (documented with comments
in the file) to help with version specific merges, where the copied
heap files reside in srcXX directories, where XX is the version.

.gitignore

@@ -1,9 +1,10 @@
 *.so
 *.o
+__pycache__
 
 /config.cache
 /config.log
 /config.status
 /Makefile
 /autom4te.cache
-/configure~
+/configure~

Makefile.in

@@ -24,16 +24,16 @@ TAP_TESTS = 1
 OBJS = src/encryption/enc_tde.o \
 src/encryption/enc_aes.o \
 src/access/pg_tde_slot.o \
-src/access/pg_tde_io.o \
-src/access/pg_tdeam_visibility.o \
 src/access/pg_tde_tdemap.o \
-src/access/pg_tdeam.o \
-src/access/pg_tdetoast.o \
-src/access/pg_tde_prune.o \
-src/access/pg_tde_vacuumlazy.o \
-src/access/pg_tde_visibilitymap.o \
-src/access/pg_tde_rewrite.o \
-src/access/pg_tdeam_handler.o \
+src$(MAJORVERSION)/access/pg_tde_io.o \
+src$(MAJORVERSION)/access/pg_tdeam_visibility.o \
+src$(MAJORVERSION)/access/pg_tdeam.o \
+src$(MAJORVERSION)/access/pg_tdetoast.o \
+src$(MAJORVERSION)/access/pg_tde_prune.o \
+src$(MAJORVERSION)/access/pg_tde_vacuumlazy.o \
+src$(MAJORVERSION)/access/pg_tde_visibilitymap.o \
+src$(MAJORVERSION)/access/pg_tde_rewrite.o \
+src$(MAJORVERSION)/access/pg_tdeam_handler.o \
 src/access/pg_tde_ddl.o \
 src/access/pg_tde_xlog.o \
 src/transam/pg_tde_xact_handler.o \

meson.build

@@ -13,20 +13,23 @@ conf_data.set_quoted('PACKAGE_TARNAME', 'pg_tde')
 configure_file(output : 'config.h',
                configuration : conf_data)
 
+pg_version = meson.project_version().substring(0,2)
+src_version = 'src' + pg_version
+
 pg_tde_sources = files(
         'src/pg_tde.c',
         'src/transam/pg_tde_xact_handler.c',
         'src/access/pg_tde_tdemap.c',
         'src/access/pg_tde_slot.c',
-        'src/access/pg_tdeam.c',
-        'src/access/pg_tdeam_handler.c',
-        'src/access/pg_tdeam_visibility.c',
-        'src/access/pg_tdetoast.c',
-        'src/access/pg_tde_io.c',
-        'src/access/pg_tde_prune.c',
-        'src/access/pg_tde_rewrite.c',
-        'src/access/pg_tde_vacuumlazy.c',
-        'src/access/pg_tde_visibilitymap.c',
+        src_version / 'access/pg_tdeam.c',
+        src_version / 'access/pg_tdeam_handler.c',
+        src_version / 'access/pg_tdeam_visibility.c',
+        src_version / 'access/pg_tdetoast.c',
+        src_version / 'access/pg_tde_io.c',
+        src_version / 'access/pg_tde_prune.c',
+        src_version / 'access/pg_tde_rewrite.c',
+        src_version / 'access/pg_tde_vacuumlazy.c',
+        src_version / 'access/pg_tde_visibilitymap.c',
         'src/access/pg_tde_ddl.c',
         'src/access/pg_tde_xlog.c',
 
@@ -51,7 +54,7 @@ pg_tde_sources = files(
         'src/pg_tde_event_capture.c',
 )
 
-incdir = include_directories('src/include', '.')
+incdir = include_directories(src_version / 'include', 'src/include', '.')
 
 deps_update = {'dependencies': contrib_mod_args.get('dependencies') + [curldep]}