BREAKING - Upgrade to upstream newlib 4.0.0 release (#7708)

* Upgrade to upstream newlib 4.0.0 release

Includes 64 bit time_t and 5 years of updates.

Binary incompatible with libraries which use time_t (due to the size
difference).  Recompiling with the new newlib should be sufficient for
most libraries, assuming source is available.

* Remove tools/sdk/libc directory, it isn't used anywhere

Somewhere along the line the copy of libc in tools/sdl/libc was taken
out of the build process.  Files in there are not used, take add'l time
to build and install on a toolchain release, and just cause confusion.
Remove them.

* Fix 64-bit time for LittleFS

The core was setting 64-bit times automatically on new file creation or
updates, but would fail when attempting to read them back due to 64/32b
confusion.

Now attempt to read 64b time, and if that fails fallback to reading 32b
time to allow both old and new FS to preserve timestamps.

* Update to jjsuwa-sys3175 additions to GCC and newlib

@jjsuwa-sys3175 contributed multiple patches to GCC, included in
the toolchain, as well as a slightly faster pgm_read_byte() macro.

* Rebuild w/addl GCC patches, new BearSSL flags

* Remove copied libgcc.a file, is contained in toolchain

tools/sdk/lwip2/include/lwip/priv/tcp_priv.h

@@ -357,7 +357,7 @@ extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS];
 #if TCP_DEBUG_PCB_LISTS
 #define TCP_REG(pcbs, npcb) do {\
                             struct tcp_pcb *tcp_tmp_pcb; \
-                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %" U16_F "\n", (void *)(npcb), (npcb)->local_port)); \
+                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %"U16_F"\n", (void *)(npcb), (npcb)->local_port)); \
                             for (tcp_tmp_pcb = *(pcbs); \
           tcp_tmp_pcb != NULL; \
         tcp_tmp_pcb = tcp_tmp_pcb->next) { \