libbeagle: add java dependency so jni hooks get built (#8524)

* libbeagle: add java dependency so jni hooks get built

* libbeagle: set BEAST_LIB instead of LD_LIBRARY_PATH

* libbeagle: use BEAST_LIB

var/spack/repos/builtin/packages/libbeagle/package.py

@@ -41,7 +41,12 @@ class Libbeagle(AutotoolsPackage):
 
     depends_on('subversion', type='build')
     depends_on('pkgconfig', type='build')
+    depends_on('java', type='build')
 
     def url_for_version(self, version):
         url = "https://github.com/beagle-dev/beagle-lib/archive/beagle_release_{0}.tar.gz"
         return url.format(version.underscored)
+
+    def setup_environment(self, spack_env, run_env):
+        prefix = self.prefix
+        run_env.prepend_path('BEAST_LIB', prefix.lib)