I did not realize that my Mac has run out of disk space and so I couldn't build the JDK, but did not know why - I thought it had something to do with an unrelated fix that I was working on.

It would be nice if our build system checked for when Xcode exits because of no disk space, and clearly reported that issue up to the user (checking build logs in this instance doesn't help)

Example of what currently the user sees:

# make images
Building target 'images' in configuration 'macosx-x86_64-server-fastdebug'
Updating images/sec-bin.zip
ld: warning: dylib (/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/modules_libs/java.base/server/libjvm.dylib) was built for newer macOS version (10.15) than being linked (10.9)
ld: warning: dylib (/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/modules_libs/java.base/server/libjvm.dylib) was built for newer macOS version (10.15) than being linked (10.9)
Creating java.instrument.jmod
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.logging.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.logging.jmod: No such file or directory
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.datatransfer.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.datatransfer.jmod: No such file or directory
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.compiler.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.compiler.jmod: No such file or directory
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.management.rmi.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.management.rmi.jmod: No such file or directory
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.naming.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.naming.jmod: No such file or directory
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.compiler.jmod] Error 1
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.datatransfer.jmod] Error 1
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.logging.jmod] Error 1
make[2]: *** [java.compiler-jmod] Error 2
make[2]: *** Waiting for unfinished jobs....
make[2]: *** [java.datatransfer-jmod] Error 2
make[2]: *** [java.logging-jmod] Error 2
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.management.rmi.jmod] Error 1
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.management.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.management.jmod: No such file or directory
make[2]: *** [java.management.rmi-jmod] Error 2
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.net.http.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.net.http.jmod: No such file or directory
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.naming.jmod] Error 1
make[2]: *** [java.naming-jmod] Error 2
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.management.jmod] Error 1
make[2]: *** [java.management-jmod] Error 2
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.net.http.jmod] Error 1
make[2]: *** [java.net.http-jmod] Error 2
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.prefs.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.prefs.jmod: No such file or directory
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.prefs.jmod] Error 1
make[2]: *** [java.prefs-jmod] Error 2
Creating interim java.base.jmod
mv: rename /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/support/images/jmods/java.desktop.jmod to /Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.desktop.jmod: No such file or directory
make[3]: *** [/Volumes/Work/bugs/8253742/jdk/build/macosx-x86_64-server-fastdebug/images/jmods/java.desktop.jmod] Error 1
make[2]: *** [java.desktop-jmod] Error 2

ERROR: Build failed for target 'images' in configuration 'macosx-x86_64-server-fastdebug' (exit code 2)