diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index 2d2a085ef933..b2852ca604b4 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -736,9 +736,11 @@ substituteStream() {
     printf "%s" "${!var}"
 }
 
+# put the content of a file in a variable
+# fail loudly if provided with a binary (containing null bytes)
 consumeEntire() {
     # read returns non-0 on EOF, so we want read to fail
-    if IFS='' read -r -N 0 $1; then
+    if IFS='' read -r -d '' $1 ; then
         echo "consumeEntire(): ERROR: Input null bytes, won't process" >&2
         return 1
     fi