If it says “At least one compiler (gcc, …) must be selected” or if it seems to find a local compiler, it means something went wrong when it looks for the sdks.
This is what is should look like:
Checking for program gcc,cc : ok /Users/mawe/work/defold/tmp/dynamo_home/ext/SDKs/XcodeDefault12.0.xctoolchain/usr/bin/clang
After the “install_ext” step, you should find the sdk packages unpacked under tmp/dynamo_home/ext/SDKs:
~/work/defold $ ls tmp/dynamo_home/ext/SDKs
drwxr-xr-x 10 mawe staff 320 Nov 11 08:37 ./
drwxr-xr-x 8 mawe staff 256 Oct 11 2018 …/
drwxr-xr-x 8 mawe staff 256 Nov 6 16:07 MacOSX10.15.sdk/
drwxr-xr-x 5 mawe staff 160 Nov 6 16:10 XcodeDefault11.5.xctoolchain/
drwxr-xr-x 5 mawe staff 160 Nov 6 17:01 XcodeDefault12.0.xctoolchain/
drwxr-xr-x 21 mawe staff 672 Nov 6 16:01 android-ndk-r20/
drwxr-xr-x 11 mawe staff 352 Nov 6 16:02 android-sdk/
drwxr-xr-x 33 mawe staff 1056 Nov 9 18:10 emsdk-1.39.16/
drwxr-xr-x 8 mawe staff 256 Nov 11 08:37 iPhoneOS14.0.sdk/
drwxr-xr-x 8 mawe staff 256 Nov 11 08:37 iPhoneSimulator14.0.sdk/
And, the paths (+ version numbers) used are set in build.py and waf_dynamo.py.
The step that fails for you currently is this (iirc) in waf_dynamo.py:
conf.check_tool(‘compiler_cc’)
conf.check_tool(‘compiler_cxx’)
So to debug it, you’ll need to printout the env beforehand and see if you spot any path issues:
print conf.env