undici-sources: check for missing dependencies

[skip changelog]

undici-sources.sh

@@ -1,6 +1,16 @@
 #!/bin/sh
-# deps: curl rpm npm nodejs-packaging-bundler
 set -e
+check_deps() {
+    deps_ec=0
+    for dep in "$@"; do
+        command -v "$dep" >/dev/null || {
+            printf 'Missing dependency: %s\n' "$dep" >&2
+            deps_ec="$((deps_ec + 1))"
+        }
+    done
+    return "$deps_ec"
+}
+check_deps curl rpm npm nodejs-packaging-bundler
 
 UNDICI_VERSION="$(rpm --specfile nodejs-undici.spec --qf '%{VERSION}\n')"; readonly UNDICI_VERSION