disable locale data download in default configuration for x86-64

add local uClibc-locale-030818.tgz file

fixing null dereference in realpath

configure: remove deprecated llvm-gcc

fix Clang-15: make int-conversion a warning

Add missing variables for GitHub CI

extra/locale/Makefile: don't always require curl/wget

configure: remove old code, make llvm-config lookup more flexible, set to Python3, remove trailing whitespace

GitHub Action: update LLVM/GTEST/Z3 versions, remove redundant steps

switch to https; fallback to curl when wget not available

Remove old CI system

Use Github Actions as CI for uClibc

Correcting use of 'lookForNew' and some rudimentary code tidying in 'configure'

Get a basic CI working again

Add a message when the bitcode compiler is specified via CC, to help diagnose cases in which CC does not point to a valid bitcode compiler.