shell: fix script's comm field if ENABLE_FEATURE_PREFER_APPLETS=y

function                                             old     new   delta
re_execed_comm                                         -      46     +46
main                                                  72      86     +14
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/0 up/down: 60/0)               Total: 60 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index e8c3084..03389f5 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -1112,8 +1112,14 @@
 	 || ENABLE_FEATURE_PREFER_APPLETS
 	 || !BB_MMU
 	) {
-		if (NUM_APPLETS > 1)
-			set_task_comm(applet_name);
+		if (NUM_APPLETS > 1) {
+			/* Careful, do not trash comm of "SCRIPT.sh" -
+			 * the case when started from e.g. #!/bin/ash script.
+			 * (not limited to shells - #!/bin/awk scripts also exist)
+			 */
+			if (re_execed_comm())
+				set_task_comm(applet_name);
+		}
 	}
 
 	parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */