diff --git a/local.mk b/local.mk
index 3f3abb9f0..7e3c77a65 100644
--- a/local.mk
+++ b/local.mk
@@ -7,4 +7,4 @@ $(foreach i, config.h $(wildcard src/lib*/*.hh), \
 
 $(GCH): src/libutil/util.hh config.h
 
-GCH_CXXFLAGS = -I src/libutil
+GCH_CXXFLAGS = $(INCLUDE_libutil)
diff --git a/src/libcmd/local.mk b/src/libcmd/local.mk
index abb7459a7..7a7c46ee2 100644
--- a/src/libcmd/local.mk
+++ b/src/libcmd/local.mk
@@ -6,7 +6,7 @@ libcmd_DIR := $(d)
 
 libcmd_SOURCES := $(wildcard $(d)/*.cc)
 
-libcmd_CXXFLAGS += -I src/libutil -I src/libstore -I src/libexpr -I src/libmain -I src/libfetchers
+libcmd_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libfetchers) $(INCLUDE_libexpr) -I src/libmain
 
 libcmd_LDFLAGS = $(EDITLINE_LIBS) $(LOWDOWN_LIBS) $(THREAD_LDFLAGS)
 
diff --git a/src/libexpr/local.mk b/src/libexpr/local.mk
index 0c3e36750..17f793ec3 100644
--- a/src/libexpr/local.mk
+++ b/src/libexpr/local.mk
@@ -11,8 +11,11 @@ libexpr_SOURCES := \
   $(wildcard $(d)/flake/*.cc) \
   $(d)/lexer-tab.cc \
   $(d)/parser-tab.cc
+# Not just for this library itself, but also for downstream libraries using this library
 
-libexpr_CXXFLAGS += -I src/libutil -I src/libstore -I src/libfetchers -I src/libmain -I src/libexpr
+INCLUDE_libexpr := -I $(d)
+
+libexpr_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libfetchers) -I src/libmain $(INCLUDE_libexpr)
 
 libexpr_LIBS = libutil libstore libfetchers
 
diff --git a/src/libfetchers/local.mk b/src/libfetchers/local.mk
index e54db4937..e229a0993 100644
--- a/src/libfetchers/local.mk
+++ b/src/libfetchers/local.mk
@@ -6,7 +6,11 @@ libfetchers_DIR := $(d)
 
 libfetchers_SOURCES := $(wildcard $(d)/*.cc)
 
-libfetchers_CXXFLAGS += -I src/libutil -I src/libstore
+# Not just for this library itself, but also for downstream libraries using this library
+
+INCLUDE_libfetchers := -I $(d)
+
+libfetchers_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libfetchers)
 
 libfetchers_LDFLAGS += $(THREAD_LDFLAGS) $(LIBGIT2_LIBS) -larchive
 
diff --git a/src/libmain/local.mk b/src/libmain/local.mk
index 5c7061863..fde28a820 100644
--- a/src/libmain/local.mk
+++ b/src/libmain/local.mk
@@ -6,7 +6,7 @@ libmain_DIR := $(d)
 
 libmain_SOURCES := $(wildcard $(d)/*.cc)
 
-libmain_CXXFLAGS += -I src/libutil -I src/libstore
+libmain_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore)
 
 libmain_LDFLAGS += $(OPENSSL_LIBS)
 
diff --git a/src/libstore/local.mk b/src/libstore/local.mk
index f86643849..7eaa317e5 100644
--- a/src/libstore/local.mk
+++ b/src/libstore/local.mk
@@ -10,7 +10,7 @@ libstore_LIBS = libutil
 
 libstore_LDFLAGS += $(SQLITE3_LIBS) $(LIBCURL_LIBS) $(THREAD_LDFLAGS)
 ifdef HOST_LINUX
- libstore_LDFLAGS += -ldl
+  libstore_LDFLAGS += -ldl
 endif
 
 $(foreach file,$(libstore_FILES),$(eval $(call install-data-in,$(d)/$(file),$(datadir)/nix/sandbox)))
@@ -27,8 +27,12 @@ ifeq ($(HAVE_SECCOMP), 1)
   libstore_LDFLAGS += $(LIBSECCOMP_LIBS)
 endif
 
+# Not just for this library itself, but also for downstream libraries using this library
+
+INCLUDE_libstore := -I $(d) -I $(d)/build
+
 libstore_CXXFLAGS += \
- -I src/libutil -I src/libstore -I src/libstore/build \
+ $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libstore) \
  -DNIX_PREFIX=\"$(prefix)\" \
  -DNIX_STORE_DIR=\"$(storedir)\" \
  -DNIX_DATA_DIR=\"$(datadir)\" \
diff --git a/src/libutil/local.mk b/src/libutil/local.mk
index 200026c1e..4ffb6bd9d 100644
--- a/src/libutil/local.mk
+++ b/src/libutil/local.mk
@@ -6,7 +6,10 @@ libutil_DIR := $(d)
 
 libutil_SOURCES := $(wildcard $(d)/*.cc $(d)/signature/*.cc)
 
-libutil_CXXFLAGS += -I src/libutil
+# Not just for this library itself, but also for downstream libraries using this library
+
+INCLUDE_libutil := -I $(d)
+libutil_CXXFLAGS += $(INCLUDE_libutil)
 
 libutil_LDFLAGS += $(THREAD_LDFLAGS) $(LIBCURL_LIBS) $(SODIUM_LIBS) $(OPENSSL_LIBS) $(LIBBROTLI_LIBS) $(LIBARCHIVE_LIBS) $(BOOST_LDFLAGS) -lboost_context
 
diff --git a/src/nix/local.mk b/src/nix/local.mk
index 1d6f560d6..55544b564 100644
--- a/src/nix/local.mk
+++ b/src/nix/local.mk
@@ -14,7 +14,7 @@ nix_SOURCES := \
   $(wildcard src/nix-instantiate/*.cc) \
   $(wildcard src/nix-store/*.cc) \
 
-nix_CXXFLAGS += -I src/libutil -I src/libstore -I src/libfetchers -I src/libexpr -I src/libmain -I src/libcmd -I doc/manual
+nix_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libfetchers) $(INCLUDE_libexpr) -I src/libmain -I src/libcmd -I doc/manual
 
 nix_LIBS = libexpr libmain libfetchers libstore libutil libcmd
 
diff --git a/src/resolve-system-dependencies/local.mk b/src/resolve-system-dependencies/local.mk
index fc48a8417..f28fdab3b 100644
--- a/src/resolve-system-dependencies/local.mk
+++ b/src/resolve-system-dependencies/local.mk
@@ -6,7 +6,7 @@ resolve-system-dependencies_DIR := $(d)
 
 resolve-system-dependencies_INSTALL_DIR := $(libexecdir)/nix
 
-resolve-system-dependencies_CXXFLAGS += -I src/libutil -I src/libstore -I src/libmain
+resolve-system-dependencies_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore) -I src/libmain
 
 resolve-system-dependencies_LIBS := libstore libmain libutil
 
diff --git a/tests/functional/plugins/local.mk b/tests/functional/plugins/local.mk
index 40350aa96..2314e1341 100644
--- a/tests/functional/plugins/local.mk
+++ b/tests/functional/plugins/local.mk
@@ -8,4 +8,4 @@ libplugintest_ALLOW_UNDEFINED := 1
 
 libplugintest_EXCLUDE_FROM_LIBRARY_LIST := 1
 
-libplugintest_CXXFLAGS := -I src/libutil -I src/libstore -I src/libexpr -I src/libfetchers
+libplugintest_CXXFLAGS := $(INCLUDE_libutil) $(INCLUDE_libstore) $(INCLUDE_libexpr) $(INCLUDE_libfetchers)
diff --git a/tests/functional/test-libstoreconsumer/local.mk b/tests/functional/test-libstoreconsumer/local.mk
index a1825c405..3e8581c57 100644
--- a/tests/functional/test-libstoreconsumer/local.mk
+++ b/tests/functional/test-libstoreconsumer/local.mk
@@ -8,7 +8,7 @@ test-libstoreconsumer_INSTALL_DIR :=
 test-libstoreconsumer_SOURCES := \
   $(wildcard $(d)/*.cc) \
 
-test-libstoreconsumer_CXXFLAGS += -I src/libutil -I src/libstore
+test-libstoreconsumer_CXXFLAGS += $(INCLUDE_libutil) $(INCLUDE_libstore)
 
 test-libstoreconsumer_LIBS = libstore libutil
 
diff --git a/tests/unit/libexpr/local.mk b/tests/unit/libexpr/local.mk
index 25810ad9c..eda65508d 100644
--- a/tests/unit/libexpr/local.mk
+++ b/tests/unit/libexpr/local.mk
@@ -23,10 +23,10 @@ libexpr-tests_EXTRA_INCLUDES = \
     -I tests/unit/libexpr-support \
     -I tests/unit/libstore-support \
     -I tests/unit/libutil-support \
-    -I src/libexpr \
-    -I src/libfetchers \
-    -I src/libstore \
-    -I src/libutil
+    $(INCLUDE_libexpr) \
+    $(INCLUDE_libfetchers) \
+    $(INCLUDE_libstore) \
+    $(INCLUDE_libutil)
 
 libexpr-tests_CXXFLAGS += $(libexpr-tests_EXTRA_INCLUDES)
 
diff --git a/tests/unit/libstore/local.mk b/tests/unit/libstore/local.mk
index 63f6d011f..960dece89 100644
--- a/tests/unit/libstore/local.mk
+++ b/tests/unit/libstore/local.mk
@@ -19,8 +19,8 @@ libstore-tests_SOURCES := $(wildcard $(d)/*.cc)
 libstore-tests_EXTRA_INCLUDES = \
     -I tests/unit/libstore-support \
     -I tests/unit/libutil-support \
-    -I src/libstore \
-    -I src/libutil
+    $(INCLUDE_libstore) \
+    $(INCLUDE_libutil)
 
 libstore-tests_CXXFLAGS += $(libstore-tests_EXTRA_INCLUDES)
 
diff --git a/tests/unit/libutil/local.mk b/tests/unit/libutil/local.mk
index 930efb90b..536607322 100644
--- a/tests/unit/libutil/local.mk
+++ b/tests/unit/libutil/local.mk
@@ -18,7 +18,7 @@ libutil-tests_SOURCES := $(wildcard $(d)/*.cc)
 
 libutil-tests_EXTRA_INCLUDES = \
     -I tests/unit/libutil-support \
-    -I src/libutil
+    $(INCLUDE_libutil)
 
 libutil-tests_CXXFLAGS += $(libutil-tests_EXTRA_INCLUDES)