Add a self_cover make target.

Makefile.PL

@@ -505,6 +505,13 @@ all_gold :
 \t rm -rf test_output
 \t exec \$(PERL) all_versions make gold
 
+self_cover : pure_all
+\t rm -rf cover_db
+\t -DEVEL_COVER_SELF=1 \$(PERL) -Mblib -MDevel::Cover cover -delete t/e2e/cover_db_*
+\t -DEVEL_COVER_SELF=1 make test
+\t DEVEL_COVER_SELF=1 \$(PERL) -Mblib -MDevel::Cover cover t/e2e/cover_db_*
+\t DEVEL_COVER_SELF=1 \$(PERL) -Mblib -MDevel::Cover cover -report html_basic
+
 mani : manifest
 \t \$(PERL) -i.bak -ne '\$\$d = "test_output/cover"; print unless /^\$\$d/; END { open M, ">>MANIFEST"; opendir D, \$\$d; print M "\$\$d/\$\$_\\n" for sort grep -f "\$\$d/\$\$_", readdir D }' MANIFEST