segfault with CDK viewFile search"/"|"?" when first search is blank, Debian w/ ncurses (6.1+20181013-1) & cdk-5.0-20180306

[c]

Hi,

I have a repeatable segfault with CDK fileView's search logic. The 
example files viewer_ex & viewer_ex2 will demonstrate the fault: invoke 
either example routine from a terminal console, select any text file, 
and enter either '/' or '?'.  Once the dialog opens to search, press 
<Enter> without any search text:  segfault.   The segfault only happens 
when the search term is blank, a prior retained search pattern will not 
segfault. The code is running on Debian 4.18.10-2 (2018-11-02) x86_64 
GNU/Linux.

It appears to my innocent eye that viewer.c at line 839, "list = 
activateCDKEntry (getPattern, 0);" cannot accept a null search value.

c