fix: make link.exe find PyPy's python*.lib

Point `LIB` environment variable to `libs` directory of extracted PyPy
on Windows, so that `link.exe` find it while building Python extensions:
https://learn.microsoft.com/en-us/cpp/build/reference/linking?view=msvc-170#link-environment-variables

Author: rominf

dist/setup/index.js

@@ -90880,6 +90880,10 @@ function findPyPyVersion(versionSpec, architecture, updateEnvironment, checkLate
             // https://cmake.org/cmake/help/latest/module/FindPython3.html#module:FindPython3
             core.exportVariable('Python3_ROOT_DIR', installDir);
             core.exportVariable('PKG_CONFIG_PATH', pythonLocation + '/lib/pkgconfig');
+            // https://learn.microsoft.com/en-us/cpp/build/reference/linking?view=msvc-170#link-environment-variables
+            if (utils_1.IS_WINDOWS) {
+                core.exportVariable('LIB', pythonLocation + '/libs');
+            }
             core.addPath(pythonLocation);
             core.addPath(_binDir);
         }

src/find-pypy.ts

@@ -93,6 +93,10 @@ export async function findPyPyVersion(
     // https://cmake.org/cmake/help/latest/module/FindPython3.html#module:FindPython3
     core.exportVariable('Python3_ROOT_DIR', installDir);
     core.exportVariable('PKG_CONFIG_PATH', pythonLocation + '/lib/pkgconfig');
+    // https://learn.microsoft.com/en-us/cpp/build/reference/linking?view=msvc-170#link-environment-variables
+    if (IS_WINDOWS) {
+      core.exportVariable('LIB', pythonLocation + '/libs');
+    }
     core.addPath(pythonLocation);
     core.addPath(_binDir);
   }