libgcrypt: fixed cross-compiling by setting ac_cv_sys_symbol_underscore=no config cache variable manually

security/libgcrypt/libgcrypt.conf

@@ -0,0 +1,18 @@
+# --- SDE-COPYRIGHT-NOTE-BEGIN ---
+# This copyright note is auto-generated by ./scripts/Create-CopyPatch.
+#
+# Filename: package/.../libgcrypt/libgcrypt.conf
+# Copyright (C) 2013 The OpenSDE Project
+#
+# More information can be found in the files COPYING and README.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License. A copy of the
+# GNU General Public License can be found in the file COPYING.
+# --- SDE-COPYRIGHT-NOTE-END ---
+
+if atstage cross; then
+	# gets wrongly detected
+	var_append configcache ' ' "ac_cv_sys_symbol_underscore=no"
+fi