build:  Use AX for pkg config

Use an autoconf archive macro for pkg config so autoconf can fill
out Requires.private in phosphor-dbus-interfaces.pc.in.

Change-Id: Ica803a0f758871b192502be5c2cdc6e166337df2
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/Makefile.am b/Makefile.am
index 464c668..6927ce4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5,8 +5,8 @@
 
 libphosphor_dbusdir = ${libdir}
 libphosphor_dbus_LTLIBRARIES = libphosphor_dbus.la
-libphosphor_dbus_la_LDFLAGS = $(SYSTEMD_LIBS) -version-info 0:0:0 -shared
-libphosphor_dbus_la_CXXFLAGS = $(SYSTEMD_CFLAGS)
+libphosphor_dbus_la_LDFLAGS = $(SYSTEMD_LIBS) $(SDBUSPLUS_LIBS) -version-info 0:0:0 -shared
+libphosphor_dbus_la_CXXFLAGS = $(SYSTEMD_CFLAGS) $(SDBUSPLUS_CFLAGS)
 
 BUILT_SOURCES = libphosphor_dbus.cpp
 CLEANFILES = libphosphor_dbus.cpp
diff --git a/configure.ac b/configure.ac
index 64c28bc..ee42dbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -28,8 +28,8 @@
         AC_MSG_ERROR([Cannot find sdbus++]))
 
     # Checks for libraries.
-    PKG_CHECK_MODULES([SYSTEMD], [libsystemd >= 221],,
-        [AC_MSG_ERROR(["systemd required and not found."])])
+    AX_PKG_CHECK_MODULES([SYSTEMD], [], [libsystemd >= 221], [], [AC_MSG_ERROR(["systemd required and not found."])])
+    AX_PKG_CHECK_MODULES([SDBUSPLUS], [], [sdbusplus], [], [AC_MSG_ERROR(["sdbusplus required and not found."])])
 
     # Checks for typedefs, structures, and compiler characteristics.
     AX_CXX_COMPILE_STDCXX_14([noext])
diff --git a/phosphor-dbus-interfaces.pc.in b/phosphor-dbus-interfaces.pc.in
index 3240872..c669aa7 100644
--- a/phosphor-dbus-interfaces.pc.in
+++ b/phosphor-dbus-interfaces.pc.in
@@ -7,5 +7,6 @@
 Description: Generated sdbusplus bindings for phosphor-dbus-interfaces.
 URL: https://github.com/openbmc/phosphor-dbus-interfaces
 Version: @VERSION@
+Requires.private: @AX_PACKAGE_REQUIRES_PRIVATE@
 Libs: -L@libdir@ -lphosphor_dbus
 Cflags: -I@includedir@