Declare meson dependency

For dependent projects to use libpeci as a subproject

Change-Id: Ifdfec228e802336b17cae887b833780cb2d8a599
Signed-off-by: Jonathan Doman <jonathan.doman@intel.com>
diff --git a/meson.build b/meson.build
index 035e1c0..0365a2b 100644
--- a/meson.build
+++ b/meson.build
@@ -77,6 +77,11 @@
 )
 install_headers('peci.h')
 
+libpeci_dep = declare_dependency(
+  link_with: libpeci,
+  include_directories: include_directories('.')
+)
+
 bindir = get_option('prefix') + '/' + get_option('bindir')
 
 executable(