esp-open-sdk fails to build

[enqack]

Error message:

./ct-ng build
make[2]: Entering directory '/esp-open-sdk/crosstool-NG'
[INFO ]  Performing some trivial sanity checks
[INFO ]  Build started 20210915.043301
[INFO ]  Building environment variables
[INFO ]  =================================================================
[INFO ]  Retrieving needed toolchain components' tarballs
[ERROR]
[ERROR]  >>
[ERROR]  >>  Build failed in step 'Retrieving needed toolchain components' tarballs'
[ERROR]  >>        called in step '(top-level)'
[ERROR]  >>
[ERROR]  >>  Error happened in: do_expat_get[scripts/build/companion_libs/210-expat.sh@741]
[ERROR]  >>        called from: do_companion_libs_get[scripts/build/companion_libs.sh@15]
[ERROR]  >>        called from: main[scripts/crosstool-NG.sh@591]
[ERROR]  >>
[ERROR]  >>  For more info on this error, look at the file: 'build.log'
[ERROR]  >>  There is a list of known issues, some with workarounds, in:
[ERROR]  >>      'share/doc/crosstool-ng/crosstool-ng-1.22.0-60-g37b07f6/B - Known issues.txt'

The error is a result of a url change for expat lib tarbar as detailed in the following issue:
pfalcon/esp-open-sdk#385