Bug#901699: libc6-dev: #include <sys/mman.h> doesn't import MAP_ANONYMOUS but man 2 mmap says it does, causing builds to break

[Joshua <joshudson@gmail.com>]

Package: libc6-dev
Version: 2.24-11+deb9u1
Severity: normal

Dear Maintainer,

#include <sys/mman.h>
#include "myplatform.h"

void *slaballoc()
{
    void *slab = mmap(... MAP_ANONYMOUS ...);
}

does not build due to MAP_ANONYMOUS not being defined. man 2 mmap says this should work.

#include <asm/mman.h>

fixes the problem but is oddly Linux specific. Use of mmap to allocate large slabs w/o using heap is reasonable on any architecture.

-- System Information:
Debian Release: 9.3
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-6-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages libc6-dev depends on:
ii  libc-dev-bin    2.24-11+deb9u1
ii  libc6           2.24-11+deb9u1
ii  linux-libc-dev  4.9.82-1+deb9u3

libc6-dev recommends no packages.

Versions of packages libc6-dev suggests:
pn  glibc-doc     <none>
ii  manpages-dev  4.10-2

-- no debconf information