diff --git a/xo-ratio/utest/CMakeLists.txt b/xo-ratio/utest/CMakeLists.txt
index 2aac113a..c1dbfaa5 100644
--- a/xo-ratio/utest/CMakeLists.txt
+++ b/xo-ratio/utest/CMakeLists.txt
@@ -16,6 +16,8 @@ if (ENABLE_TESTING)
 
     xo_self_headeronly_dependency(${SELF_EXE} xo_ratio)
     xo_dependency(${SELF_EXE} reflect)
+    # need explicit header-only dependencies, at least in submodule build
+    xo_dependency(${SELF_EXE} xo_reflectutil)
     xo_dependency(${SELF_EXE} randomgen)
     xo_dependency(${SELF_EXE} indentlog)
     xo_external_target_dependency(${SELF_EXE} Catch2 Catch2::Catch2)
diff --git a/xo-unit/utest/CMakeLists.txt b/xo-unit/utest/CMakeLists.txt
index 2ca38d03..8ff21dcb 100644
--- a/xo-unit/utest/CMakeLists.txt
+++ b/xo-unit/utest/CMakeLists.txt
@@ -20,6 +20,9 @@ if (ENABLE_TESTING)
 
     xo_self_dependency(${SELF_EXE} xo_unit)
     xo_headeronly_dependency(${SELF_EXE} xo_ratio)
+    # at least need explicit {indentlog, randomgen} deps in a submodule build
+    xo_headeronly_dependency(${SELF_EXE} indentlog)
+    xo_headeronly_dependency(${SELF_EXE} randomgen)
     xo_external_target_dependency(${SELF_EXE} Catch2 Catch2::Catch2)
 endif()