Merge branch 'stable' into docs/additional-apple-arm64-installation-instructions

Author: mpilgrem

doc/install_and_upgrade.md

@@ -115,25 +115,32 @@ If you are on macOS 10.12 (Sierra) and encounter GHC panic while building, see
 this [issue](https://github.com/commercialhaskell/stack/issues/2577)
 
 
-On Apple silicon chip (`aarch64`/`arm64` architectures), the installation for stack itself or some packages (e.g. `network`) requiring C source compilation might fail with
-`configure: error: C compiler cannot build executables.` in which case you should pass `-arch arm64` as part of
-the `CFLAGS` environment variable, which will be then picked up by the c compiler of your choice.
+On Apple silicon chip (AArch64/ARM64) architectures, the installation of Stack
+or some packages (e.g. `network`) requiring C source compilation might fail with
+`configure: error: C compiler cannot build executables`. In that case you should
+pass `-arch arm64` as part of the `CFLAGS` environment variable. This setting
+will be picked up by the C compiler of your choice.
 
 ```bash
 # Assuming BASH below
 
-# passing CFLAGS in-line with the command involving the error
+# passing CFLAGS in-line with the command giving rise to the error
 CFLAGS="-arch arm64 ${CFLAGS:-}" some_command_to_install_stack
 CFLAGS="-arch arm64 ${CFLAGS:-}" stack [build|install]
 
 # -- OR --
 
 # ~/.bash_profile
-# NOTE: only do this if you do not have to cross-compile or remember to unset CFLAGS when needed
+# NOTE: only do this if you do not have to cross-compile, or remember to unset
+# CFLAGS when needed
 export CFLAGS="-arch arm64 ${CFLAGS:-}"
 ```
 
-This instructs the C compiler to compile objects for `arm64`, which would be then successfully linked with the libraries built for `arm64`, otherwise the c compiler, invoked by `cabal` running in `x86_64`, would compile x86_64 objects and attempt to link them with existing arm64 libraries and resulting in the error above.
+The setting instructs the C compiler to compile objects for ARM64. These can
+then be linked with libraries built for ARM64. Without the instruction, the C
+compiler, invoked by Cabal running in x86-64, would compile x86-64 objects and
+attempt to link them with existing ARM64 libraries, resulting in the error
+above.
 
 ## Ubuntu