Makefile: INVALID_PROJECT_ADDONS seems always empty; no warnings emitted

context: https://forum.openframeworks.cc/t/addons-not-compiling-on-rpi3-and-4/41236

looking into how Make is "preparing" addons, it seems the condition to trigger the warning messages about missing addons never gets activated. the test: generate a fresh project, add ofxDummy in addons.make, and make: it goes through without warning even though there is some logic to detect valid/invalid addons:

https://github.com/openframeworks/openFrameworks/blob/b98cdfd0165b41fcb1bee5b87266bb1197271316/libs/openFrameworksCompiled/project/makefileCommon/config.project.mk#L182-L191

ofxDummy shows up in the INVALID_GLOBAL_ADDONS, but not in INVALID_PROJECT_ADDONS (which is the variable that would trigger the warning). it seems line 184 is not doing its job? and when swapping GLOBAL for PROJECT in the test at line 187 it does go through but then generates an error on the $(warning) statement: *** commands commence before first target. Stop. (I am thoroughly confused by the Makefile language). (tests done on macOS13.1 M1 commandline with github OF).

Start in libs/openFrameworksCompiled/project/makefileCommon/config.project.mk, especially lines 182-191, and reproduce with a fresh project containing ofxDummy in addons.make. Trace why INVALID_PROJECT_ADDONS remains empty and verify that the missing-addon warning is emitted without the commands commence before first target error.