diff --git a/pkgs/build-support/bintools-wrapper/default.nix b/pkgs/build-support/bintools-wrapper/default.nix
index 1aab26532a4..786f0f9c598 100644
--- a/pkgs/build-support/bintools-wrapper/default.nix
+++ b/pkgs/build-support/bintools-wrapper/default.nix
@@ -311,7 +311,7 @@ stdenv.mkDerivation {
 
       substituteAll ${./add-flags.sh} $out/nix-support/add-flags.sh
       substituteAll ${./add-hardening.sh} $out/nix-support/add-hardening.sh
-      substituteAll ${if stdenv.isDarwin then ../wrapper-common/utils.bash.darwin else ../wrapper-common/utils.bash} $out/nix-support/utils.bash
+      substituteAll ${../wrapper-common/utils.bash} $out/nix-support/utils.bash
     ''
 
     ##
diff --git a/pkgs/build-support/wrapper-common/utils.bash b/pkgs/build-support/wrapper-common/utils.bash
index ce569ac2b8c..8c4680a8e44 100644
--- a/pkgs/build-support/wrapper-common/utils.bash
+++ b/pkgs/build-support/wrapper-common/utils.bash
@@ -69,9 +69,9 @@ badPath() {
     # directory (including the build directory).
     test \
         "$p" != "/dev/null" -a \
-        "${p#${NIX_STORE}}" = "$p" -a \
-        "${p#${TMP:-/tmp}}" = "$p" -a \
-        "${p#${NIX_BUILD_TOP}}" = "$p"
+        "${p:0:${#NIX_STORE}}" != "$NIX_STORE" -a \
+        "${p:0:4}" != "/tmp" -a \
+        "${p:0:${#NIX_BUILD_TOP}}" != "$NIX_BUILD_TOP"
 }
 
 expandResponseParams() {
diff --git a/pkgs/build-support/wrapper-common/utils.bash.darwin b/pkgs/build-support/wrapper-common/utils.bash.darwin
deleted file mode 100644
index 8c4680a8e44..00000000000
--- a/pkgs/build-support/wrapper-common/utils.bash.darwin
+++ /dev/null
@@ -1,92 +0,0 @@
-# Accumulate suffixes for taking in the right input parameters with the `mangle*`
-# functions below. See setup-hook for details.
-accumulateRoles() {
-    declare -ga role_suffixes=()
-    if [ "${NIX_@wrapperName@_TARGET_BUILD_@suffixSalt@:-}" ]; then
-        role_suffixes+=('_FOR_BUILD')
-    fi
-    if [ "${NIX_@wrapperName@_TARGET_HOST_@suffixSalt@:-}" ]; then
-        role_suffixes+=('')
-    fi
-    if [ "${NIX_@wrapperName@_TARGET_TARGET_@suffixSalt@:-}" ]; then
-        role_suffixes+=('_FOR_TARGET')
-    fi
-}
-
-mangleVarList() {
-    local var="$1"
-    shift
-    local -a role_suffixes=("$@")
-
-    local outputVar="${var}_@suffixSalt@"
-    declare -gx ${outputVar}+=''
-    # For each role we serve, we accumulate the input parameters into our own
-    # cc-wrapper-derivation-specific environment variables.
-    for suffix in "${role_suffixes[@]}"; do
-        local inputVar="${var}${suffix}"
-        if [ -v "$inputVar" ]; then
-            export ${outputVar}+="${!outputVar:+ }${!inputVar}"
-        fi
-    done
-}
-
-mangleVarBool() {
-    local var="$1"
-    shift
-    local -a role_suffixes=("$@")
-
-    local outputVar="${var}_@suffixSalt@"
-    declare -gxi ${outputVar}+=0
-    for suffix in "${role_suffixes[@]}"; do
-        local inputVar="${var}${suffix}"
-        if [ -v "$inputVar" ]; then
-            # "1" in the end makes `let` return success error code when
-            # expression itself evaluates to zero.
-            # We don't use `|| true` because that would silence actual
-            # syntax errors from bad variable values.
-            let "${outputVar} |= ${!inputVar:-0}" "1"
-        fi
-    done
-}
-
-skip () {
-    if (( "${NIX_DEBUG:-0}" >= 1 )); then
-        echo "skipping impure path $1" >&2
-    fi
-}
-
-
-# Checks whether a path is impure.  E.g., `/lib/foo.so' is impure, but
-# `/nix/store/.../lib/foo.so' isn't.
-badPath() {
-    local p=$1
-
-    # Relative paths are okay (since they're presumably relative to
-    # the temporary build directory).
-    if [ "${p:0:1}" != / ]; then return 1; fi
-
-    # Otherwise, the path should refer to the store or some temporary
-    # directory (including the build directory).
-    test \
-        "$p" != "/dev/null" -a \
-        "${p:0:${#NIX_STORE}}" != "$NIX_STORE" -a \
-        "${p:0:4}" != "/tmp" -a \
-        "${p:0:${#NIX_BUILD_TOP}}" != "$NIX_BUILD_TOP"
-}
-
-expandResponseParams() {
-    declare -ga params=("$@")
-    local arg
-    for arg in "$@"; do
-        if [[ "$arg" == @* ]]; then
-            # phase separation makes this look useless
-            # shellcheck disable=SC2157
-            if [ -x "@expandResponseParams@" ]; then
-                # params is used by caller
-                #shellcheck disable=SC2034
-                readarray -d '' params < <("@expandResponseParams@" "$@")
-                return 0
-            fi
-        fi
-    done
-}