diff --git a/configure.ac b/configure.ac
index 4ca1c4d..696420f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,7 +13,6 @@ MDBTOOLS_VERSION_MICRO=0
 # See https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
 VERSION_INFO=4:0:0
 AC_SUBST(VERSION_INFO)
-AC_SUBST(MDBTOOLS_CFLAGS)
 
 AM_MAINTAINER_MODE([enable])
 AM_SILENT_RULES([yes])
diff --git a/libmdb.pc.in b/libmdb.pc.in
index 324dff0..f700bcc 100644
--- a/libmdb.pc.in
+++ b/libmdb.pc.in
@@ -12,4 +12,4 @@ Description: core MDB file support library
 Requires: @GLIB_PACKAGE@
 Version: @VERSION@
 Libs: -L${libdir} -lmdb
-Cflags: @MDBTOOLS_CFLAGS@
+Cflags: -I${includedir}
diff --git a/libmdbsql.pc.in b/libmdbsql.pc.in
index 0b01530..d893179 100644
--- a/libmdbsql.pc.in
+++ b/libmdbsql.pc.in
@@ -12,5 +12,4 @@ Description: libmdb based SQL engine
 Requires: libmdb
 Version: @VERSION@
 Libs: -L${libdir} -lmdbsql
-Cflags:
-
+Cflags: -I${includedir}