setupterm memory leak

[Usamah Malik]

We'd been finding memory leaks (via valgrind) in ncurses. This happens  
when ncurses is being used from tecla library. The stack is below:

==5125== 46,254 (2,236 direct, 44,018 indirect) bytes in 13 blocks are  
definitely lost in loss record 43 of 45
==5125==    at 0x400497E: calloc (vg_replace_malloc.c:397)
==5125==    by 0x5386C86: _nc_setupterm (in /usr/lib/libncurses.so.5.7)
==5125==    by 0x53871E2: setupterm (in /usr/lib/libncurses.so.5.7)
==5125==    by 0x825596E: _gl_change_terminal (in .........)

ncurse version: 5.7
platform: linux x86


On deeper analysis of setupterm we found a global variable being assigned  
chunks of memory at every setupterm call. Applying the following diff to  
lib_setup.c seems to fix it:

-------
diff ./ncurses/tinfo/lib_setup_old.c ./ncurses/tinfo/lib_setup.c
587,589c587
<       TERMINAL *oldterm = set_curterm(termp);
<
<       del_curterm(oldterm);
---
>       set_curterm(termp);
--------

ncurses is some hard-to-read code. So just putting it out here for  
analysis. Any comments would be appreciated.


Thx,

Sam