[PATCH] config.sub: Normalize arm64-* to aarch64-*

[Keno Fischer]

Apple tools use arm64-* in their triples to indicate an aarch64 CPU.
E.g. macOS 11.0 on aarch64 is `arm64-apple-darwin20.0.0`. That said,
these tools do accept the `aarch64-*` just fine as well (LLVM
normalizes internally). For config.sub, I think it makes sense to
normalize arm64-* to aarch64-*, since the latter is the established
way to refer to this architecture and likely what various configure
scripts, etc. are checking for. I tried this change on a few
autotools-based projects with `--build=arm64-apple-darwin` and
the builds seemed to go through well.
---
 ChangeLog                 | 4 ++++
 config.sub                | 3 +++
 testsuite/config-sub.data | 2 ++
 3 files changed, 9 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index c787ce9..f995b31 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2020-07-09  Keno Fischer  <keno@juliacomputing.com>
+
+       * config.sub: Normalize arm64-* to aarch64-*
+
 2020-06-28  John Ericson  <john.ericson@obsidian.systems>
 
        * config.sub: Properly parse the KERNEL-OS case.
diff --git a/config.sub b/config.sub
index ce89d5c..0634942 100755
--- a/config.sub
+++ b/config.sub
@@ -1104,6 +1104,9 @@ case $cpu-$vendor in
        xscale-* | xscalee[bl]-*)
                cpu=`echo "$cpu" | sed 's/^xscale/arm/'`
                ;;
+       arm64-*)
+               cpu=aarch64
+               ;;
 
        # Recognize the canonical CPU Types that limit and/or modify the
        # company names they are paired with.
diff --git a/testsuite/config-sub.data b/testsuite/config-sub.data
index d9639bc..197fffc 100644
--- a/testsuite/config-sub.data
+++ b/testsuite/config-sub.data
@@ -103,6 +103,8 @@ armv8a                                              
armv8a-unknown-none
 armv8b-linux-gnueabi                           armv8b-unknown-linux-gnueabi
 armv8m                                         armv8m-unknown-none
 armv8r                                         armv8r-unknown-none
+arm64-apple-darwin20.0.0                       aarch64-apple-darwin20.0.0
+arm64-apple-ios                                        aarch64-apple-ios
 aros                                           i386-pc-aros
 asmjs                                          asmjs-unknown-none
 asmjs-emscripten                               asmjs-unknown-emscripten
-- 
2.25.1