Projects which are using buildah as a library and set `TMPDIR` manually
can stumble upon a use-case where `TMPDIR` was set to a relative path.
Such as `export TMPDIR=.` in such case buildah will try to create a
temporary root using `Mkdirtemp` leading to a point where bundle is not
generated correctly since path was relative.
Following use case can be resolved by making sure that buildah always
converts relative path to absolute path and `GetTempDir` does it well.
Example reproducer with podman
```Dockerfile
FROM alpine
RUN echo hello
```
```console
export TMPDIR=.
podman build --no-cache -t test .
```
Expected failure
```console
STEP 1/2: FROM alpine
STEP 2/2: RUN echo hello
error running container: checking permissions on "buildah2341274198": stat buildah2341274198: no such file or directory
ERRO[0000] did not get container create message from subprocess: EOF
Error: building at STEP "RUN echo hello": while running runtime: exit status 1
```
Closes: RHEL-2598
Signed-off-by: Aditya R <arajan@redhat.com>
With this pkg/parse does not depend on libimage.
[NO NEW TESTS NEEDED]
Based on Miloslav's work: https://github.com/containers/podman/pull/19718
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
Jan Kaluza
flouthoc
Nalin Dahyabhai
Aditya R
Daniel J Walsh
Paul Holzinger