GDB shell is broken on Windows

[stephanosio]

The shell of the GNU Debugger (GDB) included in the Windows builds of zephyr-crosstool-ng is broken:

• Basic command line input works, but
• Backspace key does not work
• Arrow keys do not work

NOTE:

• This problem does not exist on the Windows build of GNU ARM Embedded.
• The source of the problem seems to be related to ncurses usage (or rather lack of) in the GDB.

[stephanosio]

Note that the MinGW Canadian cross compiler build process involves the compilation of all the host library dependencies (including ncurses).

[stephanosio]

It turns out setting TERM=#win32con fixes the problem (without any code changes). Figure out what the hell is going on and make that default for the Windows builds.

[stephanosio]

Related reading materials:

• https://github.com/mirror/ncurses/blob/47d2fb4537d9ad5bb14f4810561a327930ca4280/README.MinGW#L59-L61
• https://github.com/mirror/ncurses/blob/47d2fb4537d9ad5bb14f4810561a327930ca4280/man/curs_terminfo.3x#L603-L608
• https://github.com/mirror/ncurses/blob/47d2fb4537d9ad5bb14f4810561a327930ca4280/ncurses/base/lib_initscr.c#L69-L72
• https://github.com/mirror/ncurses/blob/18f51bcf99101e5bf4c737239c44064227f34db8/ncurses/win32con/win_driver.c#L626-L644
• https://github.com/mirror/ncurses/blob/47d2fb4537d9ad5bb14f4810561a327930ca4280/ncurses/base/lib_driver.c#L52-L79
• https://github.com/lhmouse/nano-win/blob/master/ncurses-6.1.patch

[stephanosio]

https://github.com/bminor/binutils-gdb/blob/f16f7b7c7447c44f4c6d23fd478c7dd767cdf642/readline/readline/terminal.c#L446-L447

GDB uses the readline library to implement the shell and the readline library was specifying the dumb terminal type when TERM environment variable is not set.