diff --git a/pkgs/build-support/trivial-builders.nix b/pkgs/build-support/trivial-builders.nix
index c889b3865f65..e73cb9c5decb 100644
--- a/pkgs/build-support/trivial-builders.nix
+++ b/pkgs/build-support/trivial-builders.nix
@@ -286,8 +286,10 @@ rec {
         set -o errexit
         set -o nounset
         set -o pipefail
+      '' + lib.optionalString (runtimeInputs != [ ]) ''
 
         export PATH="${lib.makeBinPath runtimeInputs}:$PATH"
+      '' + ''
 
         ${text}
       '';