warnings when building with clang

When building with clang, a bunch of warnings popped up.

Most of those are protobuf's rendered code related (implicit conversion long to int) and that appears to be a known issue:
https://code.google.com/p/protobuf/issues/detail?id=83

However two of those are stemming from libprocess:
../../../3rdparty/libprocess/src/encoder.hpp:125:3: warning: control may reach end of non-void function [-Wreturn-type]
../../../3rdparty/libprocess/src/process.cpp:1848:1: warning: control may reach end of non-void function [-Wreturn-type]

Unsure if the second one is a false positive.