9a1623c1dc Re-export hashbrown when enabled (Tobin C. Harding)
Pull request description:
`hashbrown` used to be exported until commit 23ee0930c7 which removed the `pub extern crate` declaration.
Found thanks to afilini (#1342)!
ACKs for top commit:
apoelstra:
ACK 9a1623c1dc
Kixunil:
ACK 9a1623c1dc
Tree-SHA512: 0363781dc06211eec59246ce54582220674d5ab2bd6e62ad15eeb97b0df6435cdf23df8306131c176b6003dde31d1e376f52981f2e69e9d2529876d3ada727e0