* posix_other: Haiku now has spawn.h
This is added per https://dev.haiku-os.org/ticket/13446
* posix_other: Add Haiku specific Dirent members
* cpuinfo: Add an implementation for Haiku
* distros: Add basic Haiku support
* encodings: update Haiku support
* fenv, math: Haiku now provides libm
* times: Add Haiku struct members
* ansi_c, osalloc: Add Haiku constants
* threads: Add Haiku support
* testament: Haiku uses LIBRARY_PATH
* nim.cfg: Update Haiku support
libnetwork should only be linked if network functions are used
* threads: Haiku does not support -pthread switch
* tworkingdir: Haiku's env is in /bin
* posix_other: add SIGKILLTHR for Haiku
* sockets: link with libnetwork on Haiku
* coro: correct ucontext.h location
http://pubs.opengroup.org/onlinepubs/009696699/basedefs/ucontext.h.html
* coro: ucontext backend is not available on Haiku
Haiku doesn't provide the <ucontext.h> header, as it was removed from POSIX
* coro: fix setjmp backend
The compiler does not allow statements after a noreturn function
* nativesockets: Haiku doesn't support AI_V4MAPPED
* system: hostOS can contains "haiku"
* os: add support for Haiku's packagefs
packagefs is read-only, but there are writable holes to the underlying
file system as well
* os: update constant for Haiku
Add a 'GenodeEnv' type and a 'componentConstructHook' to the system
module. The 'componentConstructHook' allows for detection of POSIX style
programs that exit implicitly or native Genode components that
initialize to serve RPC requests and OS signals.
This hook takes a 'GenodeEnv' argument so that the environment interface
is passed cleanly to application code after globals are initialized.
This is an typed pointer to a C++ object, procedures for accessing the
environment will be available from a Nimble library and not included in
the standard library.
The standard library has an internal pointer to the environment object
but this is not for external use, the undocumented global environment
pointer has been removed.
