Created attachment 199808 [details]
After update of protobuf to 3.6.1,1, it fails to build with GCC7 again.
google/protobuf/stubs/common.cc:52:2: error: #error "No suitable threading library available."
#error "No suitable threading library available."
The problem is that HAVE_PTHREAD is undefined. configure checks whether pthread is available and then defines HAVE_THREAD, but only does so when _THREAD_SAFE is defined, so we need to add _THREAD_SAFE to CFLAGS.
Tested on powerpc64 and amd64.
Hardware sponsored by IntegriCloud.