pg: stop building the command by default

The pg command is marked deprecated in POSIX since 1997, and this project
has thought the same since Feb 2013.  Time has come to stop shipping this
binary by default.

Reference: 956e582874
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

configure.ac

@@ -1804,8 +1804,8 @@ AM_CONDITIONAL([BUILD_MORE], [test "x$build_more" = xyes])
 
 
 AC_ARG_ENABLE([pg],
-  AS_HELP_STRING([--disable-pg], [do not build pg]),
-  [], [UL_DEFAULT_ENABLE([pg], [check])]
+  AS_HELP_STRING([--enable-pg], [build pg]),
+  [], [UL_DEFAULT_ENABLE([pg], [no])]
 )
 UL_BUILD_INIT([pg])
 UL_REQUIRES_HAVE([pg], [ncursesw, ncurses], [ncurses or ncursesw library])