Add missing p11_ver.h file to installed headers

[botantony]

Pull Request Type

• Bug fix
• New feature
• Code style / formatting / renaming
• Refactoring (no functional or API changes)
• Build / CI related changes
• Documentation
• Other (please describe):

Related Issue

Issue number: N/A

Current Behavior

make install does not install p11_ver.h header used by p11_err.h

New Behavior

p11_ver.h is installed to includes

Scope of Changes

Testing

• Existing tests
• New tests added
• Manual testing (tested locally, make install works as expected)

Additional Notes

Found in Homebrew/homebrew-core#294427

License Declaration

• I hereby agree to license my contribution under the project's license.

[mtrojnar]

"make install does not install p11_ver.h header used by p11_err.h" suggests that the distribution tarball is unbuildable. We shouldn't have to guess the claimed error symptoms though.

Is it possible that we never executed make distcheck after adding new source files? If this is the case, such repeating pattern is getting annoying. We may need make distcheck in our GitHub Actions CI.

[olszomal]

This patch installs p11_ver.h as a public header.

Without it, compiling an external application such as:

#include <libp11.h>

int main(void)
{
	return 0;
}

against the installed headers fails with:

fatal error: p11_ver.h: No such file or directory

make install and make distcheck do not catch this because they do not test an external build using only the installed headers.

LGTM, approved.