diff -ru libgpg-error.orig/src/gpg-error.c libgpg-error/src/gpg-error.c
--- libgpg-error.orig/src/gpg-error.c	2016-12-02 22:55:32.000000000 +0100
+++ libgpg-error/src/gpg-error.c	2017-09-13 22:25:10.040113800 +0200
@@ -206,7 +206,7 @@
   static const char src_prefix[] = "GPG_ERR_SOURCE_";
   static const char code_prefix[] = "GPG_ERR_";
 
-  if (!strncasecmp (src_prefix, str, sizeof (src_prefix) - 1))
+  if (!_strnicmp (src_prefix, str, sizeof (src_prefix) - 1))
     {
       gpg_err_source_t src;
 
@@ -220,14 +220,14 @@
 	  const char *src_sym;
 
 	  src_sym = gpg_strsource_sym (src << GPG_ERR_SOURCE_SHIFT);
-	  if (src_sym && !strcasecmp (str, src_sym + sizeof (src_prefix) - 1))
+	  if (src_sym && !_stricmp (str, src_sym + sizeof (src_prefix) - 1))
 	    {
 	      *err |= src << GPG_ERR_SOURCE_SHIFT;
 	      return 1;
 	    }
 	}
     }
-  else if (!strncasecmp (code_prefix, str, sizeof (code_prefix) - 1))
+  else if (!_strnicmp (code_prefix, str, sizeof (code_prefix) - 1))
     {
       gpg_err_code_t code;
 
@@ -240,7 +240,7 @@
 	{
 	  const char *code_sym = gpg_strerror_sym (code);
 	  if (code_sym
-	      && !strcasecmp (str, code_sym + sizeof (code_prefix) - 1))
+	      && !_stricmp (str, code_sym + sizeof (code_prefix) - 1))
 	    {
 	      *err |= code;
 	      return 1;
@@ -296,7 +296,7 @@
   for (src = 0; src < GPG_ERR_SOURCE_DIM; src++)
     {
       const char *src_str = gpg_strsource (src << GPG_ERR_SOURCE_SHIFT);
-      if (src_str && !strcasecmp (str, src_str))
+      if (src_str && !_stricmp (str, src_str))
 	{
 	  if (*have_source)
 	    return 0;
@@ -310,7 +310,7 @@
   for (code = 0; code < GPG_ERR_CODE_DIM; code++)
     {
       const char *code_str = gpg_strerror (code);
-      if (code_str && !strcasecmp (str, code_str))
+      if (code_str && !_stricmp (str, code_str))
 	{
 	  if (*have_code)
 	    return 0;
Nur in libgpg-error/src: gpg-error.c~.