Recognize more ARM targets.

Suggested by Dale P. Smith.

* module/system/base/target.scm (cpu-endianness): Add cases for
  "arm.*eb", "^aarch64.*be", and "aarch64".  Change "arm" case to
  "arm.*".
  (triplet-pointer-size): Allow underscore as in 'aarch64_be'.
* test-suite/tests/asm-to-bytecode.test ("cross-compilation")["armeb-unknown-linux-gnu",
  "aarch64-linux-gnu", "aarch64_be-linux-gnu"]: New tests.

module/system/base/target.scm

@@ -72,7 +72,13 @@
              (endianness big))
             ((string-match "^arm.*el" cpu)
              (endianness little))
-            ((string=? "arm" cpu)                ;ARMs are LE by default
+            ((string-match "^arm.*eb" cpu)
+             (endianness big))
+            ((string-prefix? "arm" cpu)          ;ARMs are LE by default
+             (endianness little))
+            ((string-match "^aarch64.*be" cpu)
+             (endianness big))
+            ((string=? "aarch64" cpu)
              (endianness little))
             (else
              (error "unknown CPU endianness" cpu)))))
@@ -97,7 +103,7 @@
           ((string-match "^x86_64-.*-gnux32" triplet) 4)  ; x32
 
           ((string-match "64$" cpu) 8)
-          ((string-match "64[lbe][lbe]$" cpu) 8)
+          ((string-match "64_?[lbe][lbe]$" cpu) 8)
           ((member cpu '("sparc" "powerpc" "mips" "mipsel")) 4)
           ((string-match "^arm.*" cpu) 4)
           (else (error "unknown CPU word size" cpu)))))

test-suite/tests/asm-to-bytecode.test

@@ -207,6 +207,12 @@
 
   (test-target "arm-unknown-linux-androideabi"
                (endianness little) 4)
+  (test-target "armeb-unknown-linux-gnu"
+               (endianness big) 4)
+  (test-target "aarch64-linux-gnu"
+               (endianness little) 8)
+  (test-target "aarch64_be-linux-gnu"
+               (endianness big) 8)
 
   (pass-if-exception "unknown target"
     exception:miscellaneous-error