________ running 'C:\workspace\depot_tools\python276_bin\python.exe src/webrtc/build/gyp_webrtc.py -Dextra_gyp_flag=0' in 'c:\workspace\webrtc-checkout'
Updating projects from gyp files...
Traceback (most recent call last):
File "src/webrtc/build/gyp_webrtc.py", line 128, in <module>
File "src/webrtc/build/gyp_webrtc.py", line 122, in main
File "c:\workspace\webrtc-checkout\src\build\vs_toolchain.py", line 248, in CopyVsRuntimeDlls
_CopyRuntime(out_debug, x86, "x86", debug=True)
File "c:\workspace\webrtc-checkout\src\build\vs_toolchain.py", line 203, in _CopyRuntime
_CopyRuntime2015(target_dir, source_dir, '%s140' + suffix, suffix)
File "c:\workspace\webrtc-checkout\src\build\vs_toolchain.py", line 187, in _CopyRuntime2015
source = os.path.join(source_dir, dll)
File "C:\workspace\depot_tools\python276_bin\lib\ntpath.py", line 96, in join
assert len(path) > 0
TypeError: object of type 'NoneType' has no len()
Error: Command 'C:\\workspace\\depot_tools\\python276_bin\\python.exe src/webrtc/build/gyp_webrtc.py -Dextra_gyp_flag=0' returned non-zero exit status 1 in c:\workspace\webrtc-checkout
Hook ''C:\workspace\depot_tools\python276_bin\python.exe' src/webrtc/build/gyp_webrtc.py -Dextra_gyp_flag=0' took 20.69 secs