diff --git a/lib/Makefile.am b/lib/Makefile.am
index 84bc9a36..4e04f955 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -31,6 +31,7 @@ TESTDEFS=                                                       \
 AM_CFLAGS=                                                      \
         $(WARN_CFLAGS)                                          \
         $(GMIME_CFLAGS)                                         \
+        $(XAPIAN_CFLAGS)                                        \
         $(GLIB_CFLAGS)                                          \
         $(GUILE_CFLAGS)                                         \
         $(ASAN_CFLAGS)                                          \
diff --git a/lib/index/Makefile.am b/lib/index/Makefile.am
index 602eb4dd..25f62b29 100644
--- a/lib/index/Makefile.am
+++ b/lib/index/Makefile.am
@@ -22,6 +22,7 @@ AM_CPPFLAGS=							\
 AM_CXXFLAGS=							\
 	$(WARN_CXXFLAGS)					\
 	$(GLIB_CFLAGS)						\
+	$(XAPIAN_CFLAGS)					\
 	$(ASAN_CXXFLAGS)					\
 	$(CODE_COVERAGE_CFLAGS)					\
 	-I${top_srcdir}/lib
diff --git a/mu/Makefile.am b/mu/Makefile.am
index d2fccabd..bf221d66 100644
--- a/mu/Makefile.am
+++ b/mu/Makefile.am
@@ -19,6 +19,7 @@ include $(top_srcdir)/gtest.mk
 AM_CPPFLAGS=                                                    \
 	-I${top_srcdir}/lib                                     \
 	$(GLIB_CFLAGS)                                          \
+	$(XAPIAN_CFLAGS)                                        \
 	$(CODE_COVERAGE_CFLAGS)
 
 AM_CXXFLAGS=                                                    \
@@ -61,6 +62,7 @@ mu_LDADD=                                                       \
 	${top_builddir}/lib/libmu.la                            \
 	${top_builddir}/lib/utils/libmu-utils.la                \
 	$(GLIB_LIBS)                                            \
+	$(XAPIAN_LIBS)                                          \
 	$(READLINE_LIBS)                                        \
 	$(CODE_COVERAGE_LIBS)