fix cross compilation to 32 bit arm targets

[vharron]

Summary

After syncing to ToT, I started getting this error when cross compiling to an arm target.

/usr/local/google/home/vharron/ll/cross/llvm/tools/lldb/include/lldb/Utility/ProcessStructReader.h:68:74: error: non-constant-expression cannot be narrowed from type 'unsigned long long' to 'size_t' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
                m_fields[const_name] = FieldImpl{field_type, byte_index, size};
                                                                         ^~~~

This patch adds a cast to fix the error. The cast is non-controversial because it comes after (size <= 8) is confirmed.

[vharron]

Switched to static_cast

[zturner]

lgtm

[vharron]

Committed revision 225184.

include/lldb/Utility/ProcessStructReader.h

                     return;
                 ConstString const_name = ConstString(name.c_str());
                 size_t byte_index = static_cast<size_t>(bit_offset / 8);
-                m_fields[const_name] = FieldImpl{field_type, byte_index, size};
+                m_fields[const_name] = FieldImpl{field_type, byte_index, static_cast<size_t>(size)};
             }
             size_t total_size = struct_type.GetByteSize();
             lldb::DataBufferSP buffer_sp(new DataBufferHeap(total_size,0));