patch 8.1.0526: running out of signal stack in RealWaitForChar

Problem:    Running out of signal stack in RealWaitForChar. (Vladimir Marek)
Solution:   Make the fd_set variables static.
diff --git a/src/version.c b/src/version.c
index 252d047..d3a427a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -793,6 +793,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    526,
+/**/
     525,
 /**/
     524,