link to libjvm.x on z/OS

Find Java's lib_dir to link to libjvm.x, instead of assuming
users have their LDFLAGS env variable set to that path.

binding.gyp

@@ -21,11 +21,11 @@
       ['OS=="mac"', {
         'javaver%' : "<!(awk -F/ -v h=`node findJavaHome.js` 'BEGIN {n=split(h, a); print a[2]; exit}')"
       }],
-      ['OS=="linux" or OS=="mac" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"', {
+      ['OS=="linux" or OS=="mac" or OS=="freebsd" or OS=="openbsd" or OS=="solaris" or OS=="zos"', {
         'javalibdir%': "<!(./find_java_libdir.sh <(target_arch) <(OS))"
       }],
       ['OS=="zos"', {
-        'nodever%': '<!(node -e "console.log(process.versions.node)" | cut -d"." -f1)',
+        'nodever%': '<!(node -e "console.log(process.versions.node)" | cut -d"." -f1)'
       }],
     ]
   },
@@ -117,6 +117,9 @@
                   'cflags': [ "-U_VARARG_EXT_" ],
                 }
               ]
+            ],
+            'libraries': [
+              '<(javalibdir)/libjvm.x'
             ]
           }
         ],

find_java_libdir.sh

@@ -23,7 +23,7 @@ main () {
   fi
 
   local jre_dir
-  if [[ "${java_version}" =~ (6|7|8) ]]; then
+  if [[ "${java_version}" =~ (6|7|8) && "${os}" != "zos" ]]; then
     jre_dir="${java_home}/jre/lib"
   else
     jre_dir="${java_home}/lib"
@@ -43,6 +43,8 @@ main () {
     if [[ -d ${jre_dir}/amd64/classic ]]; then lib_dir="${jre_dir}"/amd64/classic; else lib_dir="${jre_dir}"/amd64/server; fi
   elif [[ "${os}" == "linux" ]] && [[ "${target_arch}" == "s390x" || "${target_arch}" == "s390" ]]; then
     if [[ -d ${jre_dir}/s390x/classic ]]; then lib_dir="${jre_dir}"/s390x/classic; else lib_dir="${jre_dir}"/s390/classic; fi
+  elif [[ "${os}" == "zos" ]]; then
+    lib_dir="${jre_dir}"/s390x/classic
   elif [[ "${os}" == "linux" ]] && [[ "${target_arch}" == "ppc64" || "${target_arch}" == "ppc" ]]; then
     target_arch=`uname -m`
     if [[ -d ${jre_dir}/${target_arch}/classic ]]; then lib_dir="${jre_dir}"/${target_arch}/classic; else lib_dir="${jre_dir}"/${target_arch}/server; fi