diff --git a/Library/Homebrew/shims/mac/super/apr-1-config b/Library/Homebrew/shims/mac/super/apr-1-config
index e608fce1e6..d8b190a3b6 100755
--- a/Library/Homebrew/shims/mac/super/apr-1-config
+++ b/Library/Homebrew/shims/mac/super/apr-1-config
@@ -1,12 +1,13 @@
 #!/bin/bash
 
-if [[ "$HOMEBREW_CCCFG" = *a* ]]
+# shellcheck disable=SC2154
+if [[ "${HOMEBREW_CCCFG}" = *a* ]]
 then
   case "$1" in
     --cc)          echo "cc" ;;
     --cpp)         echo "cpp" ;;
-    --includedir)  echo "$HOMEBREW_SDKROOT/usr/include/apr-1" ;;
-    --includes)    echo "-isystem$HOMEBREW_SDKROOT/usr/include/apr-1" ;;
+    --includedir)  echo "${HOMEBREW_SDKROOT}/usr/include/apr-1" ;;
+    --includes)    echo "-isystem${HOMEBREW_SDKROOT}/usr/include/apr-1" ;;
     --apr-libtool) echo "glibtool" ;;
     *)
       exec xcrun apr-1-config "$@"