diff -urN ../exim-4.90.orig/src/auths/heimdal_gssapi.c ./src/auths/heimdal_gssapi.c
--- ../exim-4.90.orig/src/auths/heimdal_gssapi.c	2017-12-13 00:14:38.000000000 +0200
+++ ./src/auths/heimdal_gssapi.c	2018-01-14 17:33:38.787813000 +0200
@@ -80,9 +80,9 @@
 #ifdef MACRO_PREDEF
 
 /* Dummy values */
-void auth_heimdal_init(auth_instance *ablock) {}
-int auth_heimdal_server(auth_instance *ablock, uschar *data) {return 0;}
-int auth_heimdal_client(auth_instance *ablock, smtp_inblock *inblock,
+void auth_heimdal_gssapi_init(auth_instance *ablock) {}
+int auth_heimdal_gssapi_server(auth_instance *ablock, uschar *initial_data) {return 0;}
+int auth_heimdal_gssapi_client(auth_instance *ablock, smtp_inblock *inblock,
   smtp_outblock *outblock, int timeout, uschar *buffer, int buffsize) {return 0;}
 void auth_heimdal_gssapi_version_report(FILE *f) {}
 
diff -urN ../exim-4.90.orig/src/drtables.c ./src/drtables.c
--- ../exim-4.90.orig/src/drtables.c	2017-12-13 00:14:38.000000000 +0200
+++ ./src/drtables.c	2018-01-14 13:47:05.241327000 +0200
@@ -119,7 +119,7 @@
   {
   .driver_name =	US"heimdal_gssapi",
   .options =		auth_heimdal_gssapi_options,
-  .options_count 	 &auth_heimdal_gssapi_options_count,
+  .options_count =	&auth_heimdal_gssapi_options_count,
   .options_block =	&auth_heimdal_gssapi_option_defaults,
   .options_len =	sizeof(auth_heimdal_gssapi_options_block),
   .init =		auth_heimdal_gssapi_init,