Merge pull request uniconproject#415 from austin-barr/symtab-fix

udb: fixed safe_filelist

Author: Jafaral

uni/udb/symtab.icn

@@ -417,8 +417,8 @@ method add_to_filetab(symt)
 end
 
 method refresh_safe_filelist()
-   safe_filelist := []
-   every put(safe_filelist, !key(filetab))
+   safe_filelist := set()
+   every insert(safe_filelist, key(filetab))
 end
 
 #method add_to_procs(symt)
@@ -674,7 +674,7 @@ initially
    filetab := table()
    nametab := table()
    pkgtab  := table()
-   safe_filelist := []
+   safe_filelist := set()
 
    locals  := []
    statics := []