gnucash cmake patch

--- ./gnucash.SlackBuild.orig   2019-07-22 19:48:39.786527204 +0200
+++ ./gnucash.SlackBuild        2019-07-22 19:41:15.995533708 +0200
@@ -116,6 +116,8 @@
  \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
   -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;

+sed -i '1iinclude(CheckSymbolExists)' gnucash/register/register-gnome/CMakeLists.txt
+
   mkdir -p build
 cd build
   cmake \