Update NSPR to 4.12 and NSS to 3.23 on iOS

patches/nspr-unused-variable.patch

Index: patches/nspr-unused-variable.patch
diff --git a/patches/nspr-unused-variable.patch b/patches/nspr-unused-variable.patch
deleted file mode 100644
index c785842ce4c956ec774781e9f128218dd5492d2e..0000000000000000000000000000000000000000
--- a/patches/nspr-unused-variable.patch
+++ /dev/null
@@ -1,12 +0,0 @@
-diff --git a/nspr/pr/src/io/prfdcach.c b/nspr/pr/src/io/prfdcach.c
-index 16892bc..17b71fe 100644
---- a/nspr/pr/src/io/prfdcach.c
-+++ b/nspr/pr/src/io/prfdcach.c
-@@ -213,7 +213,6 @@ void _PR_InitFdCache(void)
- void _PR_CleanupFdCache(void)
- {
-     PRFileDesc *fd, *next;
--    PRStackElem *pop;
- 
-     for (fd = _pr_fd_cache.head; fd != NULL; fd = next)
-     {