Default amalgamation build should really include HAVE_USLEEP=1

[bengotow]

Hey! I've been using the better-sqlite3 module in Mailspring (a cross platform Electron app) for about 6 years and this is the best sqlite adapter out there.

There's just one problem I have been patching with my own fork (and now via a custom amalgamation). Without HAVE_USLEEP=1 at compile time, if sqlite encounters lock contention it tries to aquire the lock every second instead of every 10 milliseconds, assuming that the system clock does not support usleep(usec) and only sleep(seconds). Letting this loose in your application can be super mysterious - it leads to transactions taking a weirdly long time to aquire, random "database is locked" timeouts, etc. In Electron apps it's particularly likely to happen, because each window of the Electron app is it's own NodeJS process. If two application windows try to write to the database at the same time, the second window won't retry for a full second and the query will take 1s+.

I /think/ that every platform that supports NodeJS also supports usleep (I've been safely setting it and shipping Mailspring for Ubuntu 14+ / linux distros, macOS and Windows 10!)

I would absolutely love if it could be part of the blessed library and I think it would likely make other people's apps faster if they haven't realized it needs to be turned on. Thanks for making (and maintaining) a great library!

[JoshuaWise]

I tried adding this, but it caused the CI tests to fail due to sleeping for longer than expected. It worked fine on my local machine. I'm not sure why it was so slow in the CI workflow.

[JoshuaWise]

Added in 6ee3399