debug/gdb: fix tic install path, tell ncurses where to find it

ncurses 5.9 wants tic to be either one of:
- $TIC_PATH
- /usr/bin/tic

Of course, se do not want the latter, for it can be incompatible if the
ncurses in the build system is too old (eg. RHEL 5.6, Debian Lenny...).
So, force TIC_PATH to the location of our own tic.

Also, install tic alongside the other build tools, not in a sub-dir
of the toolchain installation dir.

Signed-off-by: Willy Tarreau <w@1wt.eu>
[yann.morin.1998@anciens.enib.fr: install in builtools/bin, move TIC_PATH]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # Options specific to crosstool-NG acting as a backend

 config IS_A_BACKEND

     string

     option env="CT_IS_A_BACKEND"

 config BACKEND

     bool

     default y if IS_A_BACKEND = "y" || IS_A_BACKEND = "Y"

 config BACKEND_ARCH

     string

     option env="CT_BACKEND_ARCH"

 config BACKEND_KERNEL

     string

     option env="CT_BACKEND_KERNEL"

 config BACKEND_LIBC

     string

     option env="CT_BACKEND_LIBC"