Problem including components in esp-idf project.

[woipdomain]

Hi all ,
I've been 3 days trying to import a 3rd party library under PROJECT/components.
ESP-IDF Version :ESP-IDF v4.1-dev-1086-g93a8603c5-dirty
My project structure is :
PROJECT/main
/main/src
/components/
/components/libnmea-esp32/
/components/libnmea-esp32/libnmea/

I've tried several dozens of : Makefile, CMakeLists.txt , and components.mk configuration , without success. Allways end with :

../main/nas_core.c:34:10: fatal error: libnmea.h: No such file or directory

I'm pasting the following : PROJECT/main/Makefile.txt
PROJECT/CMakeLists.txt
PROJECT/components/libnmea-esp32/CMakeLists.txt

Could someone , please clarify how components should be configured?¿

Thank you .-