[PATCH 0/3] Reentrancy

Hi,

The following patch series provides small (one line) fixes for 
newlib/libc
reentrancy when using --enable-newlib-reent-thread-local and uses the 
existing
infrastructure to do that:

   - There were a few locations on which _errno member was directly 
accessed.
As struct _reent is not available if _REENT_THREAD_LOCAL is defined, any
accesses to errno shall be done using the corresponding _REENT_ERRNO() 
macro.
Should be self-explanatory.

   - __getreent() did not check that struct _reent and _impure_ptr were
available.  Both <sys/reent.h> and impure.c, that declare and define
_impure_ptr, use similar #ifdef/ifndef gate.  If thread-local storage is 
used
the allocated objects are not related to each other.  Therefore 
__getreent()
does not exist even at a concept level, hence should not be provided at 
all.

   - As _Thread_local might not be available (as in that particular 
keyword),
<sys/reent.h> shall include <sys/cdefs.h> that will provide a correct 
mapping,
should the compiler actually support thread-local storage.  A prime 
example is
libstdc++ configure, which uses #include <math.h> in some of the 
generated
checks.  Essentially any C++ target is affected and possibly C targets 
in
near future as C23 uses thread_local, not _Thread_local.

It should be noted that libgloss is affected by similar reentrancy 
issues, but
I decided not to touch those.

-- Pekka