lib: fix hashtable in makefile and reorder include

The file "hashtable-api.h" is implemented by "hashtable.c".  In that
case, the header should be included as first to help ensure that the
ehader is self-contained (except the default header, which always comes
first for internal sources).

Author: thom311

Makefile.am

@@ -335,7 +335,6 @@ noinst_HEADERS = \
 	include/nl-aux-xfrm/nl-xfrm.h \
 	include/nl-default.h \
 	include/nl-priv-dynamic-core/cache-api.h \
-	lib/hashtable-api.h \
 	include/nl-priv-dynamic-core/nl-core.h \
 	include/nl-priv-dynamic-core/object-api.h \
 	include/nl-priv-dynamic-route/nl-priv-dynamic-route.h \
@@ -442,6 +441,7 @@ lib_libnl_3_la_SOURCES = \
 	lib/error.c \
 	lib/handlers.c \
 	lib/hash.c \
+	lib/hashtable-api.h \
 	lib/hashtable.c \
 	lib/mpls.c \
 	lib/mpls.h \

lib/hashtable.c

@@ -5,14 +5,14 @@
 
 #include "nl-default.h"
 
+#include "hashtable-api.h"
+
 #include <netlink/object.h>
 #include <netlink/hash.h>
 #include <netlink/hashtable.h>
 
 #include "nl-aux-core/nl-core.h"
 
-#include "hashtable-api.h"
-
 /**
  * @ingroup core_types
  * @defgroup hashtable Hashtable