tree 674bbe6f00aca3f80e25525c5743be37d8ac92e9
parent 616c08bc1ec604a822d354cbb0353b7994cec72d
author Thomas Lively <tlively@google.com> 1678473095 -0800
committer Thomas Lively <tlively@google.com> 1691852552 -0700

Upgrade to C++20

This will enable us to use new features including concepts and coroutines to
make our code easier to read and write.

In order to make the build work after the update, remove many newly unnecessary
overloads of operator!=, which older C++ compilers consider to be ambiguous with
their corresponding overloads of operator==, despite this having already been
fixed in the C++ spec. The operator!= overloads are not necessary in C++20
because the compiler can synthesize them automatically.