diff -ru -x '*~' openssl-1.0.2j-orig/crypto/x509/by_file.c openssl-1.0.2j/crypto/x509/by_file.c
--- openssl-1.0.2j-orig/crypto/x509/by_file.c	2016-09-26 11:49:07.000000000 +0200
+++ openssl-1.0.2j/crypto/x509/by_file.c	2016-10-13 16:54:31.400288302 +0200
@@ -97,7 +97,9 @@
     switch (cmd) {
     case X509_L_FILE_LOAD:
         if (argl == X509_FILETYPE_DEFAULT) {
-            file = (char *)getenv(X509_get_default_cert_file_env());
+            file = (char *)getenv("NIX_SSL_CERT_FILE");
+            if (!file)
+                file = (char *)getenv(X509_get_default_cert_file_env());
             if (file)
                 ok = (X509_load_cert_crl_file(ctx, file,
                                               X509_FILETYPE_PEM) != 0);