pkg-config: add argon2 dependency when not using included version

CMakeLists.txt

@@ -33,7 +33,10 @@ endif ()
 if (NOT OPENDHT_ARGON2)
     find_package(PkgConfig)
     pkg_search_module(argon2 libargon2)
-    if (NOT argon2_FOUND)
+    if (argon2_FOUND)
+        message("Argon2 found " ${argon2_req})
+        set(argon2_lib ", libargon2")
+    else ()
         message("Argon2 not found, using included version.")
         set(OPENDHT_ARGON2 ON)
     endif()

configure.ac

@@ -104,7 +104,10 @@ AC_ARG_WITH([argon2], AS_HELP_STRING([--without-argon2], [Use included Argon2]))
 AS_IF([test "x$with_argon2" != "xno"],
 			[PKG_CHECK_MODULES([Argon2], [libargon2], [have_argon2=yes], [have_argon2=no])],
 			[have_argon2=no])
-AS_IF([test "x$have_argon2" = "xyes"], [], [
+AS_IF([test "x$have_argon2" = "xyes"], [
+  AC_MSG_NOTICE([Using system Argon2])
+  AC_SUBST(argon2_lib, [", libargon2"])
+], [
 		AS_IF([test "x$with_argon2" = "xyes"], [
 				AC_MSG_ERROR([Argon2 requested but not found])
 		],[

opendht.pc.in

@@ -7,5 +7,5 @@ Description: C++ Distributed Hash Table library
 Version: @VERSION@
 Libs: -L${libdir} -lopendht
 Libs.private: -lpthread
-Requires.private: gnutls >= 3.1
+Requires.private: gnutls >= 3.1@argon2_lib@
 Cflags: -I${includedir}