Applied vodz' patches #49 and #50 (with a small correction in runshell.c)

#49: I found one memory overflow and memory leak in "ln" applet.
Last patch reduced also 54 bytes. ;)

#50: I found bug in loginutils/Makefile.in.
New patch have also new function to libbb and
aplied this to applets and other cosmetic changes.

archival/gunzip.c

@@ -119,8 +119,7 @@ static int gunzip_file (const char *path, int flags)
 	} else {
 	    error_msg_and_die("Invalid extension");
 	}
-	out_path = (char *) xcalloc(sizeof(char), length + 1);
-	strncpy(out_path, path, length);
+       out_path = xstrndup(path, length);
 			
 	/* Open output file */
 	out_file = xfopen(out_path, "w");

archival/libunarchive/get_header_ar.c

@@ -91,8 +91,7 @@ file_header_t *get_header_ar(FILE *src_stream)
 		}
 	} else {
 		/* short filenames */
-		typed->name = xcalloc(1, 16);
-		strncpy(typed->name, ar.formated.name, 16);
+               typed->name = xstrndup(ar.formated.name, 16);
 	}
 	typed->name[strcspn(typed->name, " /")]='\0';
 

archival/libunarchive/unarchive.c

@@ -58,9 +58,7 @@ char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *f
 				return(NULL);
 			}
 		}
-		full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
-		strcpy(full_name, prefix);
-		strcat(full_name, path);
+               bb_asprintf(&full_name, "%s%s", prefix, path);
 	} else {
 		full_name = file_entry->name;
 	}