d/rules: patch out wrongly linked libraries from ELFs

Adapted from proxmox-backup's 198ebc6c ("d/rules: patch out wrongly
linked libraries from ELFs")

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

debian/control

@@ -40,6 +40,7 @@ Build-Depends: bash-completion,
                librust-walkdir-2+default-dev (>= 2.3.1-~~),
                librust-xz2-0.1+default-dev,
                libstd-rust-dev,
+               patchelf,
                python3-sphinx,
                rsync,
                rustc:native,

debian/rules

@@ -32,3 +32,13 @@ override_dh_missing:
 
 override_dh_compress:
 	dh_compress -X.pdf
+
+override_dh_strip:
+	dh_strip
+	for exe in $$(find \
+	    debian/proxmox-offline-mirror/usr \
+	    debian/proxmox-offline-mirror-helper/usr \
+	    -executable -type f); \
+	do \
+	  debian/scripts/elf-strip-unused-dependencies.sh "$$exe" || true; \
+	done

debian/scripts/elf-strip-unused-dependencies.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+binary=$1
+
+exec 3< <(ldd -u "$binary" | grep -oP '[^/:]+$')
+
+patchargs=""
+dropped=""
+while read -r dep; do
+    dropped="$dep $dropped"
+    patchargs="--remove-needed $dep $patchargs"
+done <&3
+exec 3<&-
+
+if [[ $dropped == "" ]]; then
+    exit 0
+fi
+
+echo -e "patchelf '$binary' - removing unused dependencies:\n $dropped"
+patchelf $patchargs $binary