diff --git a/docs/cmdline-opts/CMakeLists.txt b/docs/cmdline-opts/CMakeLists.txt
index 5aa20dfdb8..3c020d418d 100644
--- a/docs/cmdline-opts/CMakeLists.txt
+++ b/docs/cmdline-opts/CMakeLists.txt
@@ -1,4 +1,4 @@
-set(MANPAGE "${CMAKE_BINARY_DIR}/docs/curl.1")
+set(MANPAGE "${CURL_BINARY_DIR}/docs/curl.1")
 
 # Load DPAGES and OTHERPAGES from shared file
 transform_makefile_inc("Makefile.inc" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index bd6d427072..be6f7a249f 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -105,7 +105,8 @@ if(WIN32)
 endif()
 
 target_include_directories(${LIB_NAME} INTERFACE
-  $<INSTALL_INTERFACE:include>)
+  $<INSTALL_INTERFACE:include>
+  $<BUILD_INTERFACE:${CURL_SOURCE_DIR}/include>)
 
 install(TARGETS ${LIB_NAME}
   EXPORT libcurl-target
diff --git a/tests/libtest/CMakeLists.txt b/tests/libtest/CMakeLists.txt
index ac8d33328f..6b14ad3e32 100644
--- a/tests/libtest/CMakeLists.txt
+++ b/tests/libtest/CMakeLists.txt
@@ -50,10 +50,10 @@ endif()
 
 add_custom_command(
   OUTPUT lib1521.c
-  COMMAND ${PERL_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/mk-lib1521.pl < ${CMAKE_SOURCE_DIR}/include/curl/curl.h > lib1521.c
+  COMMAND ${PERL_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/mk-lib1521.pl < ${CURL_SOURCE_DIR}/include/curl/curl.h > lib1521.c
   DEPENDS
     "${CMAKE_CURRENT_SOURCE_DIR}/mk-lib1521.pl"
-    "${CMAKE_SOURCE_DIR}/include/curl/curl.h"
+    "${CURL_SOURCE_DIR}/include/curl/curl.h"
   VERBATIM)
 
 set_property(TARGET chkdecimalpoint