Fix bss size alignment in the assembler.

Relax the requirement in the linker as well.

src/cmd/as/as.c

@@ -2425,6 +2425,9 @@ void makeheader (rtsize, rdsize)
 {
     struct exec hdr;
 
+    /* Align BSS size. */
+    count[SBSS] = (count[SBSS] + WORDSZ-1) & ~(WORDSZ-1);
+
     hdr.a_midmag = RMAGIC;
     hdr.a_text = count [STEXT];
     hdr.a_data = count [SDATA] + count [SSTRNG];

src/cmd/ld/ld.c

@@ -866,8 +866,7 @@ void readhdr (loc)
 		error (2, "bad length of text");
 	if (filhdr.a_data % W)
 		error (2, "bad length of data");
-	if (filhdr.a_bss % W)
-		error (2, "bad length of bss");
+        /* BSS segment is allowed to be unaligned. */
 }
 
 /*