From cc48de0bea23a2659d40a07530d7ebdd99126712 Mon Sep 17 00:00:00 2001 From: Paul Schneider Date: Mon, 17 Aug 2026 17:48:47 +0100 Subject: [PATCH] Makefile: dpkg-architecture -aarm64 for proper cross-build host arch MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit dpkg-buildpackage doesn't know about dotnet's --runtime flag. It uses the host arch by default, so the cross-build for arm64 produced postit_*_amd64.deb (filename mismatch with the actual arm64 .so content inside). The Debian-blessed way to do cross-builds is to set DEB_HOST_ARCH via dpkg-architecture. With -aarm64, dpkg-buildpackage will: - name the .deb postit_*_arm64.deb - accept the amd64 host as the build environment - run debhelper rules with the right DEB_* variables exported The vars from dpkg-architecture have to be exported into the same shell as dpkg-buildpackage (each make recipe line runs in its own shell), so eval and dpkg-buildpackage are chained with '\\' continuation. The warning 'GNU system type aarch64-linux-gnu does not match the CC system type x86_64-linux-gnu' is informational — it just acknowledges that we're cross-compiling. We don't compile C, so no CC toolchain is needed. --- Makefile | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Makefile b/Makefile index 963b440..2ae51bb 100644 --- a/Makefile +++ b/Makefile @@ -42,6 +42,27 @@ deb: # pattern would otherwise be re-used by dpkg-deb if the # previous run left it lying around). rm -f ../postit_*$(POSTIT_GIT_TAG)-1*.deb ../postit_*.buildinfo ../postit_*.changes + # Use dpkg-architecture to set the target arch correctly for + # cross-builds. For POSTIT_RUNTIME=linux-arm64, this exports + # DEB_HOST_ARCH=arm64 (and friends) so dpkg-buildpackage names + # the .deb postit_*_arm64.deb instead of postit_*_amd64.deb. + # For linux-x64, it sets the host arch to amd64 explicitly + # (which matches the runner — no-op, but keeps the call site + # uniform). Other RIDs are rejected. + case "$(POSTIT_RUNTIME)" in + linux-arm64) DPKG_ARCH_ARGS="-aarm64" ;; + linux-x64) DPKG_ARCH_ARGS="-aamd64" ;; + *) echo " ERROR: unsupported POSTIT_RUNTIME=$(POSTIT_RUNTIME)" >&2; exit 1 ;; + esac + # dpkg-architecture with no -t/-a flags just prints the arch + # info; with -aarm64, it exports the variables needed for a + # cross-build targeting arm64. Use 'eval' to put those vars + # in the environment of the next command. + # Chain 'eval' and 'dpkg-buildpackage' on a single shell line + # so the exported vars from dpkg-architecture are visible + # to dpkg-buildpackage. Each recipe line runs in its own + # shell, so an 'eval' on one line wouldn't affect the next. + eval $(dpkg-architecture $$DPKG_ARCH_ARGS) && \ POSTIT_GIT_URL=$(POSTIT_GIT_URL) POSTIT_GIT_TAG=$(POSTIT_GIT_TAG) POSTIT_RUNTIME=$(POSTIT_RUNTIME) \ dpkg-buildpackage -us -uc -b # dpkg-buildpackage already writes the produced .deb to