[1.75 release] Merging 'develop' to 'master' for Embarcadero fix

From: Edward Diener (eldiener_at_[hidden])
Date: 2020-10-28 18:10:51

A number of libraries have my PR to enable Embarcadero C++ clang-based 
compilers for Boost in their 'develop' branch but the branch has not 
been merged to 'master' for the 1.75 release. In the large majority of 
cases my PR for Embarcadero is the only difference between 'develop' and 
'master'. These libraries are:

assign
circular_buffer
container_hash
date_time
foreach
graph
iostreams
numeric_conversion
optional
pool
ptr_container
random
static_assert
thread
typeof
units
unordered

If any of the maintainers of these libraries could see fit to get my PR 
in 'master' from 'develop' for the 1.75 release, it would be 
appreciated. I can assert that the PR causes no problems in the 
'develop' regression tests for the aforementioned libraries. I have also 
opened up an issue for each of the aforementioned libraries in their 
Github page regarding my request.