This commit unifies the policy name for the template argument for
Native_capability_tpl to Cap_dst_policy, like suggested by Norman in the
discussion resulting from issue #145. Moreover, it takes the memcpy
operation for copying a Native_capability out of the template, which is
included by a significant bunch of files, and separates it in a library,
analog to the suggestion in issue #145.
Move the definition of '_GNU_SOURCE' from 'import-lx_hybrid.mk' to
'import-syscall.mk' because this definition may (potentially) affect all
programs that include Linux headers installed on the host - not only
hybrid Linux/Genode programs. Fixes#52
- Let hybrid Linux/Genode programs use POSIX threads for the
implementation of the Thread API.
- Prevent linkage of cxx library to hybrid Linux/Genode programs because
the cxx functionality is covered by glibc.
