Currently building gdb is impossible without an installed termcap or
curses library. But, GDB already has a very minimal termcap in the
tree to handle this situation for Windows -- gdb/stub-termcap.c. This
patch makes that the fallback for all hosts.
Testing this on GNU/Linux (by simply hacking away the termcap/curses
detection in gdb/configure.ac), we trip on:
../readline/libreadline.a(terminal.o): In function `_rl_init_terminal_io':
/home/pedro/gdb/mygit/src/readline/terminal.c:527: undefined reference to `PC'
/home/pedro/gdb/mygit/src/readline/terminal.c:528: undefined reference to `BC'
/home/pedro/gdb/mygit/src/readline/terminal.c:529: undefined reference to `UP'
/home/pedro/gdb/mygit/src/readline/terminal.c:538: undefined reference to `PC'
/home/pedro/gdb/mygit/src/readline/terminal.c:539: undefined reference to `BC'
/home/pedro/gdb/mygit/src/readline/terminal.c:540: undefined reference to `UP'
These are globals that are normally defined by termcap (or ncurses'
termcap emulation).
Now, we could just define replacements in stub-termcap.c, but
readline/terminal.c (at least the copy in our tree) has this:
#if !defined (__linux__) && !defined (NCURSES_VERSION)
# if defined (__EMX__) || defined (NEED_EXTERN_PC)
extern
# endif /* __EMX__ || NEED_EXTERN_PC */
char PC, *BC, *UP;
#endif /* !__linux__ && !NCURSES_VERSION */
which can result in readline defining the globals too. That will
usually work out in C, given that "-fcommon" is usually the default
for C compilers, but that won't work for C++, or C with -fno-common
(link fails with "multiple definition" errors)...
Mirroring those #ifdef conditions in the stub termcap screams
"brittle" to me -- I can see them changing in latter readline
versions.
Work around that by simply using __attribute__((weak)).
Windows/PE/COFF's do support weak, but not on gcc 3.4 based toolchains
(4.8.x does work). Given the file never needed the variables while it
was Windows-only, just continue not defining them there. All other
supported hosts should support this.
gdb/ChangeLog:
2015-04-06 Pedro Alves <palves@redhat.com>
Bernd Edlinger <bernd.edlinger@hotmail.de>
* configure.ac: Remove the mingw32-specific stub-termcap.o
fallback, and instead fallback to the stub termcap on all hosts.
* configure: Regenerate.
* stub-termcap.c [!__MINGW32__] (PC, BC, UP): Define as weak
symbols.
Fixes linking an --enable-build-with-cxx build on mingw:
../readline/terminal.c:278: undefined reference to `tgetnum'
../readline/terminal.c:297: undefined reference to `tgetnum'
../readline/libreadline.a(terminal.o): In function `get_term_capabilities':
../readline/terminal.c:427: undefined reference to `tgetstr'
../readline/libreadline.a(terminal.o): In function `_rl_init_terminal_io':
[etc.]
gdb/ChangeLog:
2015-03-16 Yuanhui Zhang <asmwarrior@gmail.com>
Pedro Alves <palves@redhat.com>
* gdb_curses.h (tgetnum): Mark with EXTERN_C.
* stub-termcap.c (tgetent, tgetnum, tgetflag, tgetstr, tputs)
(tgoto): Wrap with extern "C".
src/gdb/stub-termcap.c: In function 'int tputs(char*, int, int (*)())':
src/gdb/stub-termcap.c:67:22: error: too many arguments to function
outfun (*string++);
^
gdb/ChangeLog:
2015-03-16 Pedro Alves <palves@redhat.com>
Yuanhui Zhang <asmwarrior@gmail.com>
* stub-termcap.c (tputs): Change prototype.
Preparation for using this on all hosts.
Confirmed that --host=x86_64-w64-mingw32 still builds the stub
termcap.
gdb/ChangeLog:
2015-02-26 Pedro Alves <palves@redhat.com>
* windows-termcap.c: Rename to ...
* stub-termcap.c: ... this. Adjust header line.
* Makefile.in (SFILES): Refer to stub-termcap.c instead of
windows-termcap.c.
* configure: Regenerate.
* configure.ac: Refer to stub-termcap.o instead of
windows-termcap.o.
* gdb_curses.h: Mention stub-termcap.c instead of
windows-termcap.c.