fix: expose missing NATIVEWIND_OS in NativeWind plugin (#1173)

Co-authored-by: Jakub Romańczyk <lorczyslav@gmail.com>

Author: raghav-reglobe

.changeset/plugin-nativewind.md

@@ -0,0 +1,6 @@
+---
+'@callstack/repack': patch
+'@callstack/repack-plugin-nativewind': patch
+---
+
+Fix platform detection for NativeWind via `NATIVEWIND_OS` env var

packages/plugin-nativewind/src/plugin.ts

@@ -106,6 +106,11 @@ export class NativeWindPlugin implements RspackPluginInstance {
     if (this.options.checkDependencies) {
       this.ensureNativewindDependenciesInstalled(compiler.context);
     }
+    /** Set the platform if not present*/
+    const platformName = compiler.options.name;
+    if (process.env.NATIVEWIND_OS === undefined) {
+      process.env.NATIVEWIND_OS = platformName;
+    }
 
     /**
      * First, we need to process the CSS files using PostCSS.