Allow ${CHOST}-objdump (or any other override)
--- a/test/suites/debug_prefix_map.bash
+++ b/test/suites/debug_prefix_map.bash
@@ -24,7 +24,7 @@ objdump_cmd() {
     if $HOST_OS_APPLE; then
         xcrun dwarfdump -r0 $1
     else
-        objdump -W $1
+        ${OBJDUMP-objdump} -W $1
     fi
 }