BuildSystem: Enable ncurses for menuselect in Solaris 11.

The check for the library ncurses should use not use the header <curses.h> but
<ncurses.h>, because on some platforms <curses.h> is not a drop-in replacement
for <ncurses.h>: For example in Solaris, the symbol initscr is a typedef in
<curses.h> to a symbol which does not exist in the library ncurses (initscr32).
Simply use <ncurses.h> when you link to ncurses.

Furthermore in Solaris, the header <ncurses.h> is in a subdirectory
/usr/include/ncurses and not available via pkg-config.

ASTERISK-15331
ASTERISK-14935
ASTERISK-12382
ASTERISK-9107

Change-Id: Ife367776b0ccf17d3fefed868245376bfb93745d