[m-rev.] diff: Recognise aarch64-linux-musl in configure_cross script.

[Peter Wang]

tools/configure_cross:
    Support aarch64-linux-musl as a target.

NEWS:
    Update announcement.

diff --git a/NEWS b/NEWS
index adb61286a..68c1db24e 100644
--- a/NEWS
+++ b/NEWS
@@ -540,7 +540,9 @@ Portability improvements
 * We have ported Mercury to Linux AArch64 (ARM64) systems.
 
 * The `tools/configure_mingw_cross` script has been replaced by
-  `tools/configure_cross`. It now supports aarch64-linux-gnu as a target.
+  `tools/configure_cross`. It now supports aarch64-linux-gnu and
+  aarch64-linux-musl as targets (i.e. Linux on aarch64 with GNU or
+  musl C libraries).
 
 Changes to the Mercury debugger
 -------------------------------
diff --git a/tools/configure_cross b/tools/configure_cross
index 02b5630c1..87c7e8abf 100755
--- a/tools/configure_cross
+++ b/tools/configure_cross
@@ -86,9 +86,10 @@ case $host in
         mercury_cv_gcc_model_reg=yes
         mercury_cv_cannot_use_structure_assignment=yes
         ;;
-    aarch64-linux-gnu)
+    aarch64-linux-gnu | aarch64-linux-musl)
         # Taken from the config.cache file after running configure -C
-        # in a Debian 10 arm64 environment.
+        # - in a Debian 10 arm64 environment (for glibc)
+        # - in a Alpine Linux aarch64 environment (for musl)
         mercury_cv_cc_type=gcc
         mercury_cv_siginfo_t=yes
         mercury_cv_pc_access=no
-- 
2.33.1