diff --git a/var/spack/packages/openssl/package.py b/var/spack/packages/openssl/package.py
index 779c31af120..a24de20cc37 100644
--- a/var/spack/packages/openssl/package.py
+++ b/var/spack/packages/openssl/package.py
@@ -27,7 +27,9 @@ def install(self, spec, prefix):
                "zlib",
                "no-krb5",
                "shared")
-        # Remove non-standard compiler options if present
+        # Remove non-standard compiler options if present. These options are
+        # present e.g. on Darwin. They are non-standard, i.e. most compilers
+        # (e.g. gcc) will not accept them.
         filter_file(r'-arch x86_64', '', 'Makefile')
 
         make()