diff --git a/tools/Makefile.am b/tools/Makefile.am
index a28043810f1657023ecadaf903c7b5177b3385c2..a9c4b1835c28bb2214db414ff3e7c29b00d72dbc 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -1,7 +1,7 @@
 bin_PROGRAMS = dhtnode dhtchat dhtscanner
 noinst_HEADERS = tools_common.h
 
-AM_CPPFLAGS = -I../include @JsonCpp_CFLAGS@ @MsgPack_CFLAGS@
+AM_CPPFLAGS = -isystem @top_srcdir@/include @JsonCpp_CFLAGS@ @MsgPack_CFLAGS@
 
 dhtnode_SOURCES = dhtnode.cpp
 dhtnode_LDFLAGS = -lopendht -lreadline -L@top_builddir@/src/.libs @Argon2_LDFLAGS@ @GnuTLS_LIBS@