chore: update doc build

Docs/CMakeLists.txt

@@ -1,19 +1,36 @@
-# Configure Doxygen config file
+# Extract all public macros defined in LibCmo
+# However, you should note that these extratcted macros have generator expressions.
+get_target_property(LIBCMO_COMPILE_DEFINITIONS LibCmo COMPILE_DEFINITIONS)
+if (LIBCMO_COMPILE_DEFINITIONS STREQUAL "LIBCMO_COMPILE_DEFINITIONS-NOTFOUND")
+    message(FATAL_ERROR "Cannot extract compile definitions from LibCmo.")
+endif ()
+# Convert list to string for expanding in future.
+list(JOIN LIBCMO_COMPILE_DEFINITIONS " " LIBCMO_MACRO_GENERATOR_EXPRESSIONS)
+
+# We simply configure Doxygen config file first.
 configure_file(
     ${CMAKE_CURRENT_LIST_DIR}/Doxyfile.in
     ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
     @ONLY
 )
 
-# Add custom target
-add_custom_target (NeMoDocuments
-    doxygen ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
+# Then we use "file GENERATE" syntax to generate per-config truely Doxyfile used by Doxygen.
+# Because there is no "$<>" syntax in Doxyfile, so we can safely use it.
+# Please note that the generation of "file GENERATE" syntax will be postponed until the build stage.
+file(GENERATE
+    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>/Doxyfile"
+    INPUT "${CMAKE_CURRENT_BINARY_DIR}/Doxyfile"
+    TARGET LibCmo
+)
+
+# Add custom target using per-config Doxyfile
+add_custom_target (LibCmoDocuments
+    Doxygen::doxygen "${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>/Doxyfile"
     WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-    COMMENT "Generating LibCmo documentation" VERBATIM
+    COMMENT "Generating documentation" VERBATIM
 )
 
 # Install built documentation
 install (DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/html
-    CONFIGURATIONS Release RelWithDebInfo MinSizeRel
     DESTINATION ${NEMO_INSTALL_DOC_PATH}
 )