feat: Support declaring vars from env variables

Author: ovr

README.md

@@ -67,6 +67,13 @@ You can define and use variables in `path` & `host`.
             "x64"
           ]
         }
+      },
+      "feature_or_default": {
+        "default": "default",
+        "value": [
+          "env",
+          "YOUR_ENV_NAME"
+        ]
       }
     },
 }

src/index.ts

@@ -58,6 +58,13 @@ function resolveVariableValue(value: any): string | false {
     }
   }
 
+  if (Array.isArray(value) && value.length == 2) {
+    const [valueName, env_name] = value;
+    if (valueName === "env") {
+      return process.env[env_name] || false;
+    }
+  }
+
   if (value === "libc") {
     return resolveLibc();
   }