* add libnet.so and libnio.so to built-in libraries for openjdk-src build
* implement sun.misc.Unsafe.park/unpark
* implement JVM_SetClassSigners/JVM_GetClassSigners
* etc.
This allows OpenJDK to access time zone data which is normally found
under java.home, but which we must embed in the executable itself to
create a self-contained build. The VM intercepts various file
operations, looking for paths which start with a prefix specified by
the avian.embed.prefix property and redirecting those operations to an
embedded JAR.
For example, if avian.embed.prefix is "/avian-embedded", and code
calls File.exists() with a path of
"/avian-embedded/javahomeJar/foo.txt", the VM looks for a function
named javahomeJar via dlsym, calls the function to find the memory
region containing the embeded JAR, and finally consults the JAR to see
if the file "foo.txt" exists.
We now consult the JAVA_HOME environment variable to determine where
to find the system library JARs and SOs. Ultimately, we'll want to
support self-contained build, but this allows Avian to behave like a
conventional libjvm.so.
The trick is to make all destructors non-virtual. This is safe because
we never use the delete operator, which is the only case where virtual
destructors are relevant. This is a better solution than implementing
our own delete operator, because we want libraries loaded at runtime to
use the libstdc++ version, not ours.
zip files have a central directory header (which has correct information
about files) and a local file header (which sometimes does not.) Always use
the central directory versions to get accurate data.
We now support immortal objects, which the GC will scan for references
but not consider for collection. On x86_64, we allocate JIT code memory
via mmap, which lets us map memory into the bottom 2GB of the address
space, ensuring that 32-bit relative jumps and calls work.
