Re: [PATCH 6/6] compat/nedmalloc: Fix compiler warnings on linux

> On linux, when the build variable USE_NED_ALLOCATOR is set, gcc
> issues the following warnings:
>
>     In file included from compat/nedmalloc/nedmalloc.c:63:
>     .../malloc.c.h: In function 'mmap_resize':
>     .../malloc.c.h:3762: warning: implicit declaration of function 'mremap'
>     .../malloc.c.h: In function 'sys_trim':
>     .../malloc.c.h:4195: warning: comparison between pointer and integer
>
> The warnings are caused by the <sys/mman.h> header not enabling the
> (conditional) declaration of the mremap() function.  The declaration
> can be enabled by defining the _GNU_SOURCE symbol prior to including
> certain system header files. In particular, it may not be sufficient
> to simply define _GNU_SOURCE just prior to including the <sys/mman.h>
> header. (e.g. defining the symbol after including <sys/types.h> will
> be completely ineffective.)
>
> In order to suppress the warnings, we define the _GNU_SOURCE symbol
> at the start of the malloc.c.h header file.
>
> Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
> ---

>  compat/nedmalloc/malloc.c.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/compat/nedmalloc/malloc.c.h b/compat/nedmalloc/malloc.c.h
> index fdcca82..5a44dea 100644
> --- a/compat/nedmalloc/malloc.c.h
> +++ b/compat/nedmalloc/malloc.c.h
> @@ -484,6 +484,10 @@ MAX_RELEASE_CHECK_RATE   default: 4095 unless not HAVE_MMAP
>  #define DLMALLOC_VERSION 20804
>  #endif /* DLMALLOC_VERSION */
>  
> +#if defined(linux)
> +#define _GNU_SOURCE 1
> +#endif
> +
>  #ifndef WIN32
>  #ifdef _WIN32
>  #define WIN32 1