For some users, the build fails with:

dirname: illegal option -- s
usage: dirname path
usage: basename string [suffix]
       basename [-a] [-s suffix] string [...]
error: cannot read file /Users/danielfuchs/workspaces/jdk/jdk-dev/build/macosx-x64/support/gensrc/jdk.hotspot.agent/mach_excServer.c
Gensrc-jdk.hotspot.agent.gmk:52: recipe for target '/Users/danielfuchs/workspaces/jdk/jdk-dev/build/macosx-x64/support/gensrc/jdk.hotspot.agent/mach_excServer.c' failed
make[3]: *** [/Users/danielfuchs/workspaces/jdk/jdk-dev/build/macosx-x64/support/gensrc/jdk.hotspot.agent/mach_excServer.c] Error 1
make/Main.gmk:112: recipe for target 'jdk.hotspot.agent-gensrc-src' failed
make[2]: *** [jdk.hotspot.agent-gensrc-src] Error 2
make[2]: *** Waiting for unfinished jobs....

There is a potential race in a recent change in make/gensrc/Gensrc-jdk.hotspot.agent.gmk, where the new rule is missing mkdir in the recipe. Since only some people are seeing the issue, I suspect that 'mig' in Macos 10.13 creates the directory implicitly.