diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 35b4b961..723dbfaa 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -46,6 +46,7 @@ if(NOT STATIC_LIBRARY_ONLY)
     INTERFACE
       $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
       $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>
+      $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/api>
       $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/include>
       $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
     )
@@ -87,6 +88,7 @@ if(NOT SHARED_LIBRARY_ONLY)
     INTERFACE
       $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
       $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>
+      $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/api>
       $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/include>
       $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
     )
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 25610978..fede6b0c 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_policy(SET CMP0063 NEW)
 
 # Prepare "Catch" library for other executables
-set(CATCH_INCLUDE_DIR ${CMAKE_SOURCE_DIR}/external/Catch)
+set(CATCH_INCLUDE_DIR ${PROJECT_SOURCE_DIR}/external/Catch)
 add_library(Catch INTERFACE)
 target_include_directories(Catch INTERFACE ${CATCH_INCLUDE_DIR})