guix: Prefetch boost source file from working mirror

Author: luke-jr

contrib/guix/guix-build

@@ -338,6 +338,8 @@ output directory.
 EOF
 }
 
+guix-prefetch '1h00qp4z5k6lfz310xjwsmqs8fwxi6ngas51169cafz4h9fmc68y' 'https://archives.boost.io/release/1.80.0/source/boost_1_80_0.tar.bz2'
+
 # Deterministically build Bitcoin Core
 # shellcheck disable=SC2153
 for host in $HOSTS; do

contrib/guix/libexec/prelude.bash

@@ -60,6 +60,37 @@ time-machine() {
                       -- "$@"
 }
 
+################
+guix_prefetch_temp=
+trap 'test -n "$guix_prefetch_temp" && rm -rf -- "$guix_prefetch_temp"' EXIT
+
+guix-prefetch() {
+    local hash="$1" uri="$2"
+    test -n "$guix_prefetch_temp" || guix_prefetch_temp="$(mktemp)"
+    cat > "$guix_prefetch_temp" << EOF
+(use-modules (guix packages)
+             (guix download)
+             (guix build-system trivial)
+             (guix licenses))
+
+(define-public dummy
+  (package
+    (name "dummy")
+    (version "0")
+    (source (origin
+              (method url-fetch)
+              (uri "${uri}")
+              (sha256 (base32 "${hash}"))))
+    (build-system trivial-build-system)
+    (synopsis "")
+    (description "")
+    (home-page "")
+    (license gpl3+)))
+
+dummy
+EOF
+    guix build -f "$guix_prefetch_temp" --source
+}
 
 ################
 # Set common variables