Remove WGET_FLAGS from developer targets
Use -I instead of -isystem with clang-analyzer
Prevent malloc(0) when ssl_x509_names() returns no names
Use correct pointer type in sizeof()
Zero allocated elements before initializing them

For some error conditions, the error handler depends on
ctx->thr[idx]->dnsbase to be zeroed expicitly after allocation.
To prevent this type of error, zero all allocated memory even
though it will get written to in any case.