Import alloca explicitly

gnulib's alloca module was imported to gdb, and alloca is used.  This
patch is to explicitly import it.

gdb:

	* gnulib/update-gnulib.sh (IMPORTED_GNULIB_MODULE): Add
	alloca.
	* gnulib/import/Makefile.am: Re-generated.
	* gnulib/import/Makefile.in: Likewise..
	* gnulib/import/m4/gnulib-cache.m4: Likewise.
diff --git a/gdb/gnulib/update-gnulib.sh b/gdb/gnulib/update-gnulib.sh
index ec1a8e8..2d983ba 100644
--- a/gdb/gnulib/update-gnulib.sh
+++ b/gdb/gnulib/update-gnulib.sh
@@ -30,6 +30,7 @@
 
 # The list of gnulib modules we are importing in GDB.
 IMPORTED_GNULIB_MODULES="\
+    alloca \
     dirent \
     dirfd \
     fnmatch-gnu \