Re: [PATCH] GDB: Fix detection of ELF support when configuring with -Werror

[Simon Marchi <simark@simark.ca>]

On 2020-11-11 4:20 a.m., Alex Richardson via Gdb-patches wrote:
> I was getting "I'm sorry, Dave, I can't do that.  Symbol format `elf64-littleriscv' unknown."
> errors after updating from GDB 8.3 to 10. Bisecting showed that since
> commit 1ff6de031241c59d0ff9fa01d3c0a4049b0e97c9, bfd.h depends on strncmp()
> being present, so configuring with -Werror results in the check for ELF
> support in BFD failing:
> .../gdb/gdb/../bfd/elf-bfd.h: In function 'bfd_section_is_ctf':
> .../gdb/gdb/../bfd/elf-bfd.h:3086:10: error: implicit declaration of function 'strncmp' [-Werror=implicit-function-declaration]
>    return strncmp (name, ".ctf", 4) == 0 && (name[4] == 0 || name[4] == '.');
> ---
>  gdb/acinclude.m4 | 1 +
>  gdb/configure    | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/gdb/acinclude.m4 b/gdb/acinclude.m4
> index 64574e26314..68520d6d938 100644
> --- a/gdb/acinclude.m4
> +++ b/gdb/acinclude.m4
> @@ -266,6 +266,7 @@ AC_DEFUN([GDB_AC_CHECK_BFD], [
>      [AC_LINK_IFELSE(
>         [AC_LANG_PROGRAM(
>  	  [#include <stdlib.h>
> +	   #include <string.h>
>  	   #include "bfd.h"
>  	   #include "$4"],
>  	  [return $3;]
> diff --git a/gdb/configure b/gdb/configure
> index 4a03cd9c3ec..ddbeefe426e 100755
> --- a/gdb/configure
> +++ b/gdb/configure
> @@ -16745,6 +16745,7 @@ else
>    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>  /* end confdefs.h.  */
>  #include <stdlib.h>
> +	   #include <string.h>
>  	   #include "bfd.h"
>  	   #include "elf-bfd.h"
>  int
> @@ -16858,6 +16859,7 @@ else
>    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
>  /* end confdefs.h.  */
>  #include <stdlib.h>
> +	   #include <string.h>
>  	   #include "bfd.h"
>  	   #include "mach-o.h"
>  int
> -- 
> 2.29.1
> 

Since elf-bfd.h uses strncmp, I think it should include string.h.  Is there a good reason not to do that?

Simon