build as sub components with defined exports

minor tweak to apriltag_python include directives

Author: j-medland

libs/apriltag_python/CMakeLists.txt

@@ -4,7 +4,7 @@
 get_target_property(APRILTAG_INCLUDES_LIST ${PROJECT_NAME}-include INTERFACE_INCLUDE_DIRECTORIES)
 set(ADDITIONAL_INCLUDE_DIRECTIVES "")
 foreach(ITEM ${APRILTAG_INCLUDES_LIST})
-    set(ADDITIONAL_INCLUDE_DIRECTIVES "${ADDITIONAL_INCLUDE_DIRECTIVES}-I\"${ITEM}\";")
+    LIST(APPEND ADDITIONAL_INCLUDE_DIRECTIVES "-I\"${ITEM}\"")
 endforeach()
 
 if(BUILD_PYTHON_WRAPPER)
@@ -30,7 +30,7 @@ if (NOT Python3_NOT_FOUND AND NOT Numpy_NOT_FOUND AND PYTHONLIBS_FOUND AND BUILD
     endforeach()
 
     add_custom_command(OUTPUT apriltag_pywrap.o
-        COMMAND ${CMAKE_C_COMPILER} ${PY_CFLAGS} -I${CMAKE_CURRENT_BINARY_DIR} ${ADDITIONAL_INCLUDE_DIRECTIVES}-c -o apriltag_pywrap.o ${CMAKE_CURRENT_SOURCE_DIR}/apriltag_pywrap.c
+        COMMAND ${CMAKE_C_COMPILER} ${PY_CFLAGS} -I${CMAKE_CURRENT_BINARY_DIR} ${ADDITIONAL_INCLUDE_DIRECTIVES} -c -o apriltag_pywrap.o ${CMAKE_CURRENT_SOURCE_DIR}/apriltag_pywrap.c
         DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/apriltag_pywrap.c ${CMAKE_CURRENT_BINARY_DIR}/apriltag_detect.docstring.h ${CMAKE_CURRENT_BINARY_DIR}/apriltag_py_type.docstring.h)
     add_custom_command(OUTPUT apriltag${PY_EXT_SUFFIX}
         COMMAND ${PY_LINKER} ${PY_LDFLAGS} -lm -Wl,-rpath,lib apriltag_pywrap.o "$<TARGET_FILE:apriltag-detector>" "$<TARGET_FILE:apriltag-tags>" -o apriltag${PY_EXT_SUFFIX}