Delete bundled copy of NSS and replace with README.

patches/nspr-overflow.patch

-diff --git a/nspr/lib/ds/plarena.c b/nspr/lib/ds/plarena.c
-index 95e1931..689496d 100644
---- a/nspr/lib/ds/plarena.c
-+++ b/nspr/lib/ds/plarena.c
-@@ -93,6 +93,9 @@ PR_IMPLEMENT(void) PL_InitArenaPool(
-         pool->mask = PR_BITMASK(PR_CeilingLog2(align));
- 
-     pool->first.next = NULL;
-+    /* Set all three addresses in pool->first to the same dummy value.
-+     * These addresses are only compared with each other, but never
-+     * dereferenced. */
-     pool->first.base = pool->first.avail = pool->first.limit =
-         (PRUword)PL_ARENA_ALIGN(pool, &pool->first + 1);
-     pool->current = &pool->first;
-@@ -144,10 +147,14 @@ PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
- {
-     PLArena *a;   
-     char *rp;     /* returned pointer */
-+    PRUint32 nbOld;
- 
-     PR_ASSERT((nb & pool->mask) == 0);
-     
-+    nbOld = nb;
-     nb = (PRUword)PL_ARENA_ALIGN(pool, nb); /* force alignment */
-+    if (nb < nbOld)
-+        return NULL;
- 
-     /* attempt to allocate from arenas at pool->current */
-     {
-@@ -208,6 +215,7 @@ PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
-             PL_MAKE_MEM_NOACCESS((void*)a->avail, a->limit - a->avail);
-             rp = (char *)a->avail;
-             a->avail += nb;
-+            PR_ASSERT(a->avail <= a->limit);
-             /* the newly allocated arena is linked after pool->current 
-             *  and becomes pool->current */
-             a->next = pool->current->next;
-@@ -230,6 +238,8 @@ PR_IMPLEMENT(void *) PL_ArenaGrow(
- {
-     void *newp;
- 
-+    if (PR_UINT32_MAX - size < incr)
-+        return NULL;
-     PL_ARENA_ALLOCATE(newp, pool, size + incr);
-     if (newp)
-         memcpy(newp, p, size);
-diff --git a/nspr/lib/ds/plarena.h b/nspr/lib/ds/plarena.h
-index 8dcfb3e..3e51f83 100644
---- a/nspr/lib/ds/plarena.h
-+++ b/nspr/lib/ds/plarena.h
-@@ -139,32 +139,37 @@ void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
-         PLArena *_a = (pool)->current; \
-         PRUint32 _nb = PL_ARENA_ALIGN(pool, nb); \
-         PRUword _p = _a->avail; \
--        PRUword _q = _p + _nb; \
--        if (_q > _a->limit) { \
-+        if (_nb < nb) { \
-+            _p = 0; \
-+        } else if (_nb > (_a->limit - _a->avail)) { \
-             _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
-         } else { \
--            _a->avail = _q; \
-+            _a->avail += _nb; \
-         } \
-         p = (void *)_p; \
--        PL_MAKE_MEM_UNDEFINED(p, nb); \
--        PL_ArenaCountAllocation(pool, nb); \
-+        if (p) { \
-+            PL_MAKE_MEM_UNDEFINED(p, nb); \
-+            PL_ArenaCountAllocation(pool, nb); \
-+        } \
-     PR_END_MACRO
- 
- #define PL_ARENA_GROW(p, pool, size, incr) \
-     PR_BEGIN_MACRO \
-         PLArena *_a = (pool)->current; \
-         PRUint32 _incr = PL_ARENA_ALIGN(pool, incr); \
--        PRUword _p = _a->avail; \
--        PRUword _q = _p + _incr; \
--        if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
--            _q <= _a->limit) { \
-+        if (_incr < incr) { \
-+            p = NULL; \
-+        } else if (_a->avail == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
-+            _incr <= (_a->limit - _a->avail)) { \
-             PL_MAKE_MEM_UNDEFINED((unsigned char *)(p) + size, incr); \
--            _a->avail = _q; \
-+            _a->avail += _incr; \
-             PL_ArenaCountInplaceGrowth(pool, size, incr); \
-         } else { \
-             p = PL_ArenaGrow(pool, p, size, incr); \
-         } \
--        PL_ArenaCountGrowth(pool, size, incr); \
-+        if (p) {\
-+            PL_ArenaCountGrowth(pool, size, incr); \
-+        } \
-     PR_END_MACRO
- 
- #define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)