refactor(build): Switch dist checksumming to more modular approach

.github/workflows/release.yml

@@ -27,9 +27,6 @@ jobs:
       - name: Build source package
         run: |
           make dist
-      - name: Generate checksums of release artifacts
-        run: |
-          make decasify-${{ env.VERSION }}.sha256.txt
       - name: Publish Release
         uses: softprops/action-gh-release@v2
         with:

Makefile.am

@@ -22,6 +22,7 @@ CLEANFILES =
 
 CARGO_FEATURE_ARGS = --features full
 
+include $(top_srcdir)/build-aux/dist_checksums.mk
 include $(top_srcdir)/build-aux/rust_boilerplate.mk
 
 SEMVER = $(shell $(AWK) -F\" '/^version/ { print $$2 }' Cargo.toml)
@@ -37,13 +38,6 @@ REL_ROCK = $(PACKAGE_NAME)-$(SEMVER)-$(ROCKREV).src.rock
 
 EXTRA_decasify_SOURCES += $(REL_SPEC) $(DEV_SPEC)
 
-DIST_ARTIFACTS := $(wildcard $(distdir).tar.zst $(distdir).zip $(REL_ROCK))
-
-# Output both a file to attach to releases and stdout so CI build logs can be
-# audited as matching what is actually posted.
-$(PACKAGE_NAME)-%.sha256.txt: $(DIST_ARTIFACTS)
-	sha256sum $^ | tee $@
-
 .PHONY: rockspecs
 rockspecs: $(DEV_SPEC) $(REL_SPEC)
 

build-aux/ax_dist_checksums.m4

@@ -0,0 +1,6 @@
+AC_DEFUN([AX_DIST_CHECKSUMS], [
+
+        AX_PROGVAR([sha256sum])
+        AX_PROGVAR([tee])
+
+])

build-aux/dist_checksums.mk

@@ -0,0 +1,11 @@
+# Prepend to function that runs after compressing dist archives
+am__post_remove_distdir = $(checksum_dist); $(am__post_remove_distdir )
+
+# Output both a file that can be attatched to releases and also write STDOUT
+# for the sake of CI build logs so they can be audited as matching what is
+# eventually posted. The list of files checksummed is a glob (even though we
+# know an exact pattern) to avoid errors for formats not generated.
+checksum_dist = \
+	shopt -s nullglob ; \
+	$(SHA256SUM) $(distdir)*.{tar.{gz,bz2,lz,xz,zst},zip} | $(TEE) $(distdir).sha256.txt
+

configure.ac

@@ -6,6 +6,7 @@ AM_INIT_AUTOMAKE([foreign tar-pax dist-zstd dist-zip no-dist-gzip color-tests])
 AM_SILENT_RULES([yes])
 
 AX_GIT_VERSION
+AX_DIST_CHECKSUMS
 AX_TRANSFORM_PACKAGE_NAME
 
 AC_PROG_AWK