qperf fails to build on both x86-64 and ppc64le due to lack of
dependency.

qperf depends on /usr/share/perl5/core_perl/pods/perldiag.pod file, and if it
does not exist (as on a clean env), it shows:

  couldn't find diagnostic data in /usr/share/perl5/core_perl/pods/perldiag.pod /usr/local/lib/perl5/site_perl /usr/local/share/perl5/site_perl /usr/lib/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib/perl5/core_perl /usr/share/perl5/core_perl . ./mkhelp at /usr/share/perl5/core_perl/diagnostics.pm line 259, <POD_DIAG> line 704.
  Compilation failed in require at ./mkhelp line 5.
  BEGIN failed--compilation aborted at ./mkhelp line 5.
  make[1]: *** [Makefile:475: help.c] Error 2
  make[1]: *** Waiting for unfinished jobs....
  couldn't find diagnostic data in /usr/share/perl5/core_perl/pods/perldiag.pod /usr/local/lib/perl5/site_perl /usr/local/share/perl5/site_perl /usr/lib/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib/perl5/core_perl /usr/share/perl5/core_perl . ./mkman at /usr/share/perl5/core_perl/diagnostics.pm line 259, <POD_DIAG> line 704.
  Compilation failed in require at ./mkman line 6.
  BEGIN failed--compilation aborted at ./mkman line 6.
  make[1]: *** [Makefile:471: qperf.1] Error 2

This file is provided by perl-dev on Alpine, thus, adding it to
$makedepends