Merge branch 'ds/sparse-checkout-malformed-pattern-fix'

Certain sparse-checkout patterns that are valid in non-cone mode
led to segfault in cone mode, which has been corrected.

* ds/sparse-checkout-malformed-pattern-fix:
  sparse-checkout: refuse to add to bad patterns
  sparse-checkout: fix OOM error with mixed patterns
  sparse-checkout: fix segfault on malformed patterns

diff --cc builtin/sparse-checkout.c
Simple merge

diff --cc dir.c
Simple merge

diff --cc t/t1091-sparse-checkout-builtin.sh
Simple merge