Toolchains: Update to GCC 10.5.0

All toolchain dependencies are circa the GCC 10.5.0 release:

  GCC 10.5.0, binutils 2.40, gmp 6.2.1, mpfr 4.1.1, mpc 1.3.1, isl 0.24

Native:

 * arm - mini2g, nano2g works
       - ipod6g hangs at logo display
 * mips - xduoox3 works
 * m68k - binaries untested

Hosted:

 * arm - samsungypr0 works
 * mips - xduoox3ii works
 * Android NDK - unchanged at GCC 4.9.4

Change-Id: Ic157255d76030e66325719e64331f553cb7c4363

tools/toolchain-patches/apple_silicon-zlib.patch

@@ -1,14 +1,14 @@
 diff --git a/zlib/zutil.h b/zlib/zutil.h
-index ed6b127e..3186e991 100644
+index 4b596adf..66d54cc3 100644
 --- a/zlib/zutil.h
 +++ b/zlib/zutil.h
-@@ -118,17 +118,8 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
+@@ -130,17 +130,8 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
  #  endif
  #endif
  
 -#if defined(MACOS) || defined(TARGET_OS_MAC)
 +#if defined(MACOS)
- #  define OS_CODE  0x07
+ #  define OS_CODE  7
 -#  ifndef Z_SOLO
 -#    if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
 -#      include <unix.h> /* for fdopen */
@@ -20,4 +20,4 @@ index ed6b127e..3186e991 100644
 -#  endif
  #endif
  
- #ifdef TOPS20
+ #ifdef __acorn