Enable building LLVM with about-to-be deprecated toolchains for best chance of succeeding with the build.
diff --git a/emsdk.py b/emsdk.py
index e83b2c8..4a96d8b 100644
--- a/emsdk.py
+++ b/emsdk.py
@@ -1043,6 +1043,9 @@
# Target macOS 10.14 at minimum, to support widest range of Mac devices from "Early 2008" and newer:
# https://en.wikipedia.org/wiki/MacBook_(2006-2012)#Supported_operating_systems
cmdline += ['-DCMAKE_OSX_DEPLOYMENT_TARGET=10.14']
+ # To enable widest possible chance of success for building, let the code compile through with older toolchains
+ # that are about to be deprecated by upstream LLVM.
+ cmdline += ['-DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON']
cmdline += extra_cmake_args + [src_root]
print('Running CMake: ' + str(cmdline))
