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

Junio C Hamano wrote:

Ramsay Jones [off-list ref] writes:

quoted

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 <redacted>
---

Hmmmm, is this even worth worrying about?  I somehow thought this
was only meant to replace malloc on non GNU systems...

Maybe not. I certainly won't be using it on Linux. But I wanted to
test the previous patch on Linux and it didn't compile cleanly, so ...
(It passed all tests BTW).

ATB,
Ramsay Jones