Changed to a more portable Node version check in binding.gyp
diff --git a/binding.gyp b/binding.gyp
index 3a3a881..de10d9d 100644
--- a/binding.gyp
+++ b/binding.gyp
@@ -46,10 +46,11 @@
       # io.js always reports versions >0 and always exports ALPN symbols.
       # Therefore, Node's major version will be truthy if and only if it
       # supports ALPN. The output of "node -v" is v[major].[minor].[patch],
-      # like "v4.1.1" in a recent version. We use grep to extract just the
-      # major version. "4", would be the output for the example.
+      # like "v4.1.1" in a recent version. We use cut to split by period and
+      # take the first field (resulting in "v[major]"), then use cut again
+      # to take all but the first character, removing the "v".
     'defines': [
-      'TSI_OPENSSL_ALPN_SUPPORT=<!(node -v | grep -oP "(?<=v)(\d+)(?=\.\d+\.\d+)")'
+      'TSI_OPENSSL_ALPN_SUPPORT=<!(node --version | cut -d. -f1 | cut -c2-)'
     ],
     'include_dirs': [
       '.',