Add metadata file.

meta/libraries.json

@@ -0,0 +1,14 @@
+{
+    "key": "predef",
+    "name": "Predef",
+    "authors": [
+        "Rene Rivera"
+    ],
+    "description": "This library defines a set of compiler, architecture, operating system, library, and other version numbers from the information it can gather of C, C++, Objective C, and Objective C++ predefined macros or those defined in generally available headers.",
+    "category": [
+        "Miscellaneous"
+    ],
+    "maintainers": [
+        "Rene Rivera <grafikrobot -at- gmail.com>"
+    ]
+}