which: fix it so the manpage will respect alternatives

To fix:

  file /usr/share/man/man1/which.1 conflicts between attempted installs
  of debianutils-doc-4.8.1-r0.core2_64 and which-doc-2.21-r3.core2_64

(From OE-Core rev: ba304046307cd741694b25215b562d5f05c9c7a5)

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/which/which_2.21.bb

@@ -30,3 +30,6 @@ do_configure_prepend() {
 
 ALTERNATIVE_${PN} = "which"
 ALTERNATIVE_PRIORITY = "100"
+
+ALTERNATIVE_${PN}-doc = "which.1"
+ALTERNATIVE_LINK_NAME[which.1] = "${mandir}/man1/which.1"

meta/recipes-support/debianutils/debianutils_4.8.1.bb

@@ -40,6 +40,9 @@ ALTERNATIVE_PRIORITY="30"
 ALTERNATIVE_${PN} = "add-shell installkernel remove-shell savelog tempfile which"
 ALTERNATIVE_${PN}-run-parts = "run-parts"
 
+ALTERNATIVE_${PN}-doc = "which.1"
+ALTERNATIVE_LINK_NAME[which.1] = "${mandir}/man1/which.1"
+
 ALTERNATIVE_LINK_NAME[add-shell]="${sbindir}/add-shell"
 ALTERNATIVE_LINK_NAME[installkernel]="${sbindir}/installkernel"
 ALTERNATIVE_LINK_NAME[remove-shell]="${sbindir}/remove-shell"