make build-if-not-exists and build-if-changed always build

[mokagio]

That's because they look for dist/app.js but webpack uses fullhash in the name, i.e. dist/app.20fd562f4b5b27e29042.js

simplenote-electron/Makefile

Line 21 in f5d463f

SIMPLENOTE_JS := $(THIS_DIR)/dist/app.js

simplenote-electron/webpack.config.js

Line 23 in f5d463f

filename: 'app.[fullhash].js',

[mokagio]

That's because they look for dist/app.js but webpack uses fullhash in the name

This behavior was introduced in #1543

[codebykat]

Right, I don't think we want to revert the hash, rather improve the Makefile detection... I tinkered with it a bit in #3225 but I'm not sure if that helps or not.