maint: fix 'make dist' in VPATH build

A diff of 'make dist' from in-tree vs. a VPATH build showed
that we were missing docs/api_extension/*.patch files, but
shipping other files that we didn't need.

* bootstrap.conf (gnulib_extra_files): Don't distribute files we
don't care about.
* docs/Makefile.am (patches): Perform wildcard correctly.

bootstrap.conf

@@ -165,6 +165,16 @@ tar        -
 # Automake requires that ChangeLog exist.
 touch ChangeLog || exit 1
 
+# Override bootstrap's list - we don't use mdate-sh or texinfo.tex.
+gnulib_extra_files="
+        $build_aux/install-sh
+        $build_aux/missing
+        $build_aux/depcomp
+        $build_aux/config.guess
+        $build_aux/config.sub
+        doc/INSTALL
+"
+
 
 bootstrap_epilogue()
 {

docs/Makefile.am

@@ -64,7 +64,7 @@ dot_html_in = $(notdir $(wildcard $(srcdir)/*.html.in)) todo.html.in \
       $(patsubst $(srcdir)/%,%,$(wildcard $(srcdir)/internals/*.html.in))
 dot_html = $(dot_html_in:%.html.in=%.html)
 
-patches = $(wildcard api_extension/*.patch)
+patches = $(patsubst $(srcdir)/%,%,$(wildcard $(srcdir)/api_extension/*.patch))
 
 xml = \
   libvirt-api.xml \