Comment on the need for CGO_ENABLED=1 to support cross-compilation (#3735)

Author: maru-ava

scripts/constants.sh

@@ -27,9 +27,7 @@ fi
 # We use "export" here instead of just setting a bash variable because we need
 # to pass this flag to all child processes spawned by the shell.
 export CGO_CFLAGS="-O2 -D__BLST_PORTABLE__"
-# While CGO_ENABLED doesn't need to be explicitly set, it produces a much more
-# clear error due to the default value change in go1.20.
-export CGO_ENABLED=1
+export CGO_ENABLED=1 # Required for cross-compilation
 
 # Disable version control fallbacks
 export GOPROXY="https://proxy.golang.org"