jni.h location and Makefiles

[John Keiser]

    Shouldn't we either include jni.h with our distribution or make the user
point to another directory with jni.h in it?  Perhaps have configure look
for it in C_INCLUDE_PATH (which is where I am currently setting the
directory)?
    I'm saying this because most of the time I can't compile stuff until I
do this.  Am I missing something that everyone else is doing by default?
--John Keiser