I notice that running bash ./configure ... leaves an a.out file in the root directory of the jdk, but only after adding configure flags
--with-toolchain-type=clang --with-toolchain-path=/usr/lib/llvm-3.9/bin (i.e. not when building with default gcc) Probably there's a test compilation whose output does not go into the build/ directory, and whose output is not cleaned up.
