build: Do away with older and newer deps

We copy the 'newer' variant to the canonical locations.
No need to implement manual branching, we have git since decades.

Part-of: <https://gitlab.gnome.org/World/Phosh/squeekboard/-/merge_requests/620>

debian/rules

@@ -24,13 +24,6 @@ endif
 export RUSTFLAGS = --remap-path-prefix=$(CURDIR)=/remap-pwd $(xgot)
 
 
-distrel := $(shell lsb_release --codename --short)
-ifneq (,$(filter $(distrel),bookworm))
-	newer = true
-else
-	newer = false
-endif
-
 %:
 	dh $@ --builddirectory=_build --buildsystem=meson
 
@@ -38,6 +31,6 @@ endif
 # causing Cargo to refuse to build with a crates.io copy
 override_dh_auto_configure:
 	[ ! -f Cargo.lock ] || rm Cargo.lock
-	dh_auto_configure -- -Dnewer=$(newer) -Donline=false
+	dh_auto_configure -- -Donline=false
 
 override_dh_autoreconf: