lib_path for libjava in top level

[Aaron W. LaFramboise]

Presently in the top-level Makefile.def, libjava is not among the 
libraries that have a specified TARGET_LIB_PATH.  For libraries that 
have this, such as libgcc, libgomp, libstdc++, and others, it ensures 
that RPATH is set appropriately when in-tree executables are run as part 
of the build or test process.  For instance:

target_modules = { module= libgomp; lib_path=.libs; };

Because on this, on i386-pc-mingw32, gcj-dbtool.exe fails to run when 
libgcj is compiled as a dynamic library, if there is not already a 
binary-compatible libgcj installed on the system somewhere that the 
loader can find it.

Is this an oversight, or there some other mechanism that is supposed to 
make this work, that perhaps doesn't work on Windows?