Merge commit 'f4d091fbe1f4' into 4.next

diff --cc src/src/pdkim/pdkim.c
index d9fbb8e8bca23bd6f4981f3c312e0620f94d6b16,bd05c51b53e8074ceb6f3fd02b2dec63b54213be..a099f94b00d61c66e989f2e0a859367e8c2666f2
--- 1/src/src/pdkim/pdkim.c
--- 2/src/src/pdkim/pdkim.c
+++ b/src/src/pdkim/pdkim.c
@@@ -1554,6 -1543,6 +1543,9 @@@ if (  pdkim_headcat(&col, hdr, ";", "a=
    if (!pdkim_headcat(&col, hdr, NULL, ";", ""))
      goto BAIL;
    }
++  else 
++    if(!pdkim_headcat(&col, hdr, ";", "b=", ""))
++      goto BAIL;
  
  rc = strdup(hdr->str);