Enable dynamic reent for multicore/multithread

Dynamic_reent enables each core or thread to have its own local store.
W/o it, crashes can happen if two cores are running newlib code at the
same time.  printf_float, for instance.

Also completely remove the fake locking routines and supply them in the
core directly.

patches/lib-dynamic-reent.patch

@@ -0,0 +1,15 @@
+diff --git a/newlib/libc/include/sys/config.h b/newlib/libc/include/sys/config.h
+index 4bc8d29bf..23d465407 100644
+--- a/newlib/libc/include/sys/config.h
++++ b/newlib/libc/include/sys/config.h
+@@ -4,6 +4,10 @@
+ #include <machine/ieeefp.h>  /* floating point macros */
+ #include <sys/features.h>	/* POSIX defs */
+
++#ifndef __DYNAMIC_REENT__
++#define __DYNAMIC_REENT__
++#endif
++
+ #ifdef __aarch64__
+ #define MALLOC_ALIGNMENT 16
+ #endif

patches/lib-weak-locks.patch

@@ -1,8 +1,17 @@
 diff --git a/newlib/libc/misc/lock.c b/newlib/libc/misc/lock.c
-index 545511e78..984b51f72 100644
+index 545511e78..bae9ec187 100644
 --- a/newlib/libc/misc/lock.c
 +++ b/newlib/libc/misc/lock.c
-@@ -92,63 +92,73 @@ struct __lock {
+@@ -83,7 +83,7 @@ subroutines are required for linking multi-threaded applications.
+ */
+
+ /* dummy lock routines and static locks for single-threaded apps */
+-
++#if 0
+ #ifndef __SINGLE_THREAD__
+
+ #include <sys/lock.h>
+@@ -92,66 +92,77 @@ struct __lock {
    char unused;
  };
 
@@ -86,3 +95,7 @@ index 545511e78..984b51f72 100644
  void
  __retarget_lock_release_recursive (_LOCK_T lock)
  {
+ }
+
+ #endif /* !defined(__SINGLE_THREAD__) */
++#endif