configure: make SERVICE_DIR static

There is really no value in making this a configuration option since
nobody modifies it anywhere.  Remove the configuration to simplify.

Change-Id: Ia36d5b45a7942c2f26f039b194f10fa5d08aa13c
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/configure.ac b/configure.ac
index 95113d9..15f1eac 100755
--- a/configure.ac
+++ b/configure.ac
@@ -22,8 +22,5 @@
 AC_CHECK_HEADER(systemd/sd-bus.h, ,[AC_MSG_ERROR([Could not find systemd/sd-bus.h...systemd development package required])])
 # Checks for typedefs, structures, and compiler characteristics.
 
-AC_ARG_VAR(SERVICE_DIR, [Location of service files.])
-AS_IF([test "x$SERVICE_DIR" == "x"], [SERVICE_DIR="/etc/slp/services/"])
-AC_DEFINE_UNQUOTED([SERVICE_DIR], ["$SERVICE_DIR"], [Location of service files.])
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT
diff --git a/slp_message_handler.cpp b/slp_message_handler.cpp
index a99cd54..ea90a11 100644
--- a/slp_message_handler.cpp
+++ b/slp_message_handler.cpp
@@ -1,5 +1,3 @@
-#include "config.h"
-
 #include "endian.hpp"
 #include "slp.hpp"
 #include "slp_meta.hpp"
@@ -20,6 +18,8 @@
 namespace internal
 {
 
+static constexpr auto SERVICE_DIR = "/etc/slp/services/";
+
 buffer prepareHeader(const Message& req)
 {
     uint8_t length =