Build exits cleanly even if there are errors

[spinningarrow]

In build.ts when there is an error, the script simply logs it without exiting with a non-zero exit code.

This causes build systems to continue with the build process even though the code may not compile.

A process.exit(1) after the log should fix this.

[seanpmaxwell]

hmm, can you create a pull request?

[seanpmaxwell]

Done