notmuch: fix broken notmuch-emacs-mua

The old notmuch-emacs-mua's shebang is `/bin/sh`,
but that script requires some bashisms.

srcpkgs/notmuch/patches/bash_absolute.patch

@@ -0,0 +1,10 @@
+--- configure.orig
++++ configure
+@@ -563,6 +563,7 @@ printf "Checking for bash... "
+ if command -v ${BASH} > /dev/null; then
+     have_bash=1
+     bash_absolute=$(command -v ${BASH})
++    bash_absolute=$(readlink -f "$bash_absolute")
+     printf "Yes (%s).\n" "$bash_absolute"
+ else
+     have_bash=0

srcpkgs/notmuch/template

@@ -1,7 +1,7 @@
 # Template file for 'notmuch'
 pkgname=notmuch
 version=0.28
-revision=2
+revision=3
 hostmakedepends="perl pkg-config python-Sphinx python-devel python3-Sphinx python3-devel"
 makedepends="bash-completion gmime3-devel talloc-devel xapian-core-devel"
 short_desc="Thread-based email index, search, and tagging"