accessors: build warning

[igaw]

../libnvme/src/nvme/generate-accessors.c: In function ‘main’:
../libnvme/src/nvme/generate-accessors.c:1706:21: warning: implicit declaration of function ‘asprintf’; did you mean ‘vsprintf’? [-Wimplicit-function-declaration]
 1706 |         dont_care = asprintf(&guard, "_%s_", get_filename(conf.h_fname));
      |                     ^~~~~~~~
      |                     vsprintf
[230/230] Linking target nvme

[martin-belanger]

I will take care of it.

[igaw]

Can't remember how I was able to create this one. It appeared when I was playing around with the PR before merging. Anyway, as it doesn't appear in our CI build I think we just close it. No need to waste time here.