[Bug-gnubg] GLU check on darwin

[Daisuke Takahashi]

Hello,

On gnubg 1.05.002, configure with --with-board3d always fails on darwin, even 
though the system has gtkglext and glu and both of them are configurable from 
pkg-config.

The reason of this configure fail seems to be a variable have_glu. The variable 
is kept to be undefined (without any check) on darwin (at configure.ac:143),

    if test "x$darwin" = "xyes"; then
        have_canberra="no"
    elif test "x$with_gtk" != "xno"; then
        PKG_CHECK_MODULES(CANBERRA, [libcanberra-gtk], have_canberra="yes", 
AC_MSG_WARN([no libcanberra-gtk support]))
        PKG_CHECK_MODULES(GLU, [glu], have_glu="yes", AC_MSG_WARN([no glu 
support]))
    fi

however, at configure.ac:328,

    if test  "$with_board3d" != "no" && test "$with_gtk" != "no" && test 
"x$have_gtk" = "xyes" && test "x$have_gtkglext" = "xyes" -a "x$have_glu" = 
"xyes"; then
        AC_DEFINE(USE_BOARD3D,1, [Define if you want to use the 3d boards])
        no_board3d="no"
    fi

    if test "$with_board3d" = "yes" && test "$no_board3d" = "yes"; then
        AC_MSG_ERROR([board3d requested but gtk or gtkglext not found])
    fi

configure requests the variable to be "yes" to enable board3d.

Regards,
Daisuke