Implement secure_getenv(3) if not provided by stdlib

[zyga]

This patch changes the previous approach to falling back to unsecure
getenv if the standard library (e.g. musl) didn't provide the
secure_getenv() function. Snap confine now provides an internal copy of
the required library function instead.

Signed-off-by: Zygmunt Krynicki zygmunt.krynicki@canonical.com

[zyga]

Spread failures are caused by out-of-date things in the image. Let me try to get spread to update everything first.

[chipaca]

you could add __attribute__((nonnull)) so that gcc and clang warn you if you pass in null, i think?

[chipaca]

also warn_unused_result fwiw

[zyga]

Nice, I'll do it

[chipaca]

always use braces around ifs that aren't single-liners? Or maybe just always use braces around ifs.

[zyga]

{ } are like seat belts, will do

[chipaca]

+1 with a nit and some suggestions

[zyga]

Thanks for the review. I'll update the pull request.

[chipaca]

you could add __attribute__((nonnull)) so that gcc and clang warn you if you pass in null, i think?

[chipaca]

also warn_unused_result fwiw

[zyga]

Nice, I'll do it

[chipaca]

always use braces around ifs that aren't single-liners? Or maybe just always use braces around ifs.

[zyga]

{ } are like seat belts, will do

[lool]

Looks good to me too, thanks for adding this