[boost] [release] Boost 1.71.0 Release Candidate 1

The first release candidates for the 1.71.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.71.0.rc1/source/> The SHA256 checksums are as follows: 7fadf835372325d7a287b1c45310c4f96811eb1e4809933a5a400d529df38d0e boost_1_71_0_rc1.7z c857a86fb1223c7a256414151e2d1dcd4691b56197aa1329e087e92502191434 boost_1_71_0_rc1.tar.bz2 07c07cad079fed3f0175cbd7097740a333c2cdc6c899ac433dea87d1224d726d boost_1_71_0_rc1.tar.gz bc1674ba3e11635fc2effbddc2ed69aecaced3901f81a6a2aae7b77f34e4cf76 boost_1_71_0_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy.