pkg-config: Create and install a pkg-config file

Let automake create the openbsc.pc and then install it
into the pkg-config directory of ${libdir}. This is done
in preparation for the public API that will be added soon.

The advertised include directory will be ${incluedir}/openbsc-1.0
to follow userspace practive from glib/gtk/cairo/freetype2 and
many more.
diff --git a/Makefile.am b/Makefile.am
index 1ba0604..deaba0f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -3,5 +3,8 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
 SUBDIRS = include src tests
 
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = openbsc.pc
+
 #dist-hook:
 #	rm -rf `find $(distdir) -name .svn`
diff --git a/configure.in b/configure.in
index 69fa1b5..7bc8b63 100644
--- a/configure.in
+++ b/configure.in
@@ -19,6 +19,7 @@
 dnl Checks for typedefs, structures and compiler characteristics
 
 AC_OUTPUT(
+    openbsc.pc
     include/openbsc/Makefile
     include/vty/Makefile
     include/Makefile
diff --git a/openbsc.pc.in b/openbsc.pc.in
new file mode 100644
index 0000000..0d00831
--- /dev/null
+++ b/openbsc.pc.in
@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/openbsc-1.0
+
+Name: OpenBSC
+Description: OpenBSC base station controller
+Requires:
+Version: @VERSION@
+Libs: -L${libdir} -lopenbsc
+Cflags: -I${includedir}