Custom libraries in sketchbook/libraries not supported

[peplin]

We need to support multiple library paths.

[rei-vilo]

Try this as an exploration:

# Comments: 
#   := immediate assignment
#   ~ is accepted in makefile but requires translation

# List of Arduino libraries

ARDUINO_DIR := /Applications/Mpide.app/Contents/Resources/Java
ARDUINO_LIB_PATH := $(ARDUINO_DIR)/libraries

DIRS1 := $(realpath $(sort $(dir $(wildcard $(ARDUINO_LIB_PATH)/*/*.h $(ARDUINO_LIB_PATH)/*/*/*.h))))
ARDUINO_LIBS := $(subst $(ARDUINO_DIR)/libraries/,, $(filter-out %xample %xamples %ocumentation,$(DIRS1)))

# List of user's Libraries - capital L on my HDD

SKETCHBOOK_DIR := $(wildcard ~/Documents/Arduino/_Projets)
SKETCHBOOK_LIB_PATH := $(SKETCHBOOK_DIR)/Libraries

DIRS2 := $(realpath $(sort $(dir $(wildcard $(SKETCHBOOK_LIB_PATH)/*/*.h $(SKETCHBOOK_LIB_PATH)/*/*/*.h))))
SKETCHBOOK_LIBS :=$(subst $(SKETCHBOOK_DIR)/Libraries/,,$(filter-out %xample %xamples %ocumentation,$(DIRS2)))

all:
    @echo " \n"
    @echo "----Arduino"
    @echo "----ARDUINO_LIBS"
    @echo $(ARDUINO_LIBS)
    @echo " "
    @echo "----Sketchbook"
    @echo "----SKETCHBOOK_LIBS"
    @echo $(SKETCHBOOK_LIBS)
    @echo " \n"