Makefile_6_project

$ cat src/main/Makefile
# build shared library with -fPIC, -shared
CFLAGS   = -g # -O3 -fPIC # CXXFLAGS for .cpp
CPPFLAGS = -MMD -MP # -I../foo
LDFLAGS  = # -L../foo -Wl,-rpath,'$$ORIGIN/../foo' # -shared
LDLIBS   = # -lfoo
#CC      = $(CXX) # link with CXX for .cpp

# target name is basename of one of the source files
main : $(patsubst %.c,%.o,$(wildcard *.c)) # .cpp
-include *.d
clean : ; -rm -fr *.o *.d
.PHONY : clean
$

$ cat src/Makefile
LIBDIRS = bar foo
MAINDIRS = main1 main2

all : $(LIBDIRS) $(MAINDIRS)
foo : bar
main1 : foo
main2 : foo

$(MAINDIRS) : $(LIBDIRS)
$(LIBDIRS) :
	$(MAKE) -C $@
	cp $@/$@ $@/lib$@.so
$(MAINDIRS) :
	$(MAKE) -C $@
clean :
	for dir in $(LIBDIRS) $(MAINDIRS); do \
		$(MAKE) -C $$dir $@; \
	done
.PHONY : $(LIBDIRS) $(MAINDIRS) all clean
$

$ cat .vscode/launch.json
{
  "configurations": [
    {
      "type": "lldb",
      "request": "launch",
      "name": "Debug",
      "program": "${fileDirname}/${fileBasenameNoExtension}",
      "args": [],
      "cwd": "${fileDirname}",
      "preLaunchTask": "make",
    }
  ]
}
$

$ cat .vscode/tasks.json
{
  "tasks": [
    {
      "label": "make",
      "type": "shell",
      "options": {
        "cwd": "${workspaceFolder}/src",
      },
      "command": "/usr/bin/make",
    }
  ]
}
$

$ cat .vscode/settings.json
{
  "clangd.fallbackFlags": [
    // "-std=c++2a",
    // "-I${workspaceFolder}/boost",
    "-I${workspaceFolder}/src/foo",
    "-I${workspaceFolder}/src/bar",
  ],
}
$