*: better string sharing

   text   data    bss    dec    hex filename
 849427    441   7556 857424  d1550 busybox_old
 849355    441   7556 857352  d1508 busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/archival/bzip2.c b/archival/bzip2.c
index f1c84d6..fdb8b93 100644
--- a/archival/bzip2.c
+++ b/archival/bzip2.c
@@ -88,7 +88,7 @@
 			if (n2 != n) {
 				if (n2 >= 0)
 					errno = 0; /* prevent bogus error message */
-				bb_perror_msg(n2 >= 0 ? "short write" : "write error");
+				bb_perror_msg(n2 >= 0 ? "short write" : bb_msg_write_error);
 				return -1;
 			}
 		}
@@ -118,7 +118,7 @@
 	while (1) {
 		count = full_read(STDIN_FILENO, rbuf, IOBUF_SIZE);
 		if (count < 0) {
-			bb_perror_msg("read error");
+			bb_perror_msg(bb_msg_read_error);
 			total = -1;
 			break;
 		}
diff --git a/archival/libunarchive/decompress_unxz.c b/archival/libunarchive/decompress_unxz.c
index 3f93929..1302e29 100644
--- a/archival/libunarchive/decompress_unxz.c
+++ b/archival/libunarchive/decompress_unxz.c
@@ -86,7 +86,7 @@
 		if (rd) {
 			rd = safe_read(src_fd, membuf + insz, rd);
 			if (rd < 0) {
-				bb_error_msg("read error");
+				bb_error_msg(bb_msg_read_error);
 				total = -1;
 				break;
 			}
diff --git a/archival/libunarchive/decompress_unzip.c b/archival/libunarchive/decompress_unzip.c
index 33e877e..bccd026 100644
--- a/archival/libunarchive/decompress_unzip.c
+++ b/archival/libunarchive/decompress_unzip.c
@@ -1072,7 +1072,7 @@
 		bytebuffer_offset = 0;
 		bytebuffer_size = full_read(gunzip_src_fd, &bytebuffer[count], bytebuffer_max - count);
 		if ((int)bytebuffer_size < 0) {
-			bb_error_msg("read error");
+			bb_error_msg(bb_msg_read_error);
 			return 0;
 		}
 		bytebuffer_size += count;