fix(bridge): read TNB_LIB_PATH via os.Getenv first (Windows support)

On Windows, Node's process.env write goes through SetEnvironmentVariableW,
which never touches the CRT environ block that libc getenv reads — so the
noembed lib-path override introduced for the c-shared bridge was invisible
to Go, and tsgo fell back to the executable-adjacent path (node.exe's dir)
and panicked: 'lib.d.ts does not exist; this executable may be misplaced'
(issue #9).

getenvLive now tries os.Getenv first — Go resolves it through the Win32
environment block, the one channel that sees SetEnvironmentVariableW — and
falls back to libc getenv for POSIX, where Go's runtime-init snapshot can
miss a setenv issued immediately before koffi.load. Both set-before-dlopen
channels are covered.

Author: johnsoncodehk

patches/typescript-go/0005-noembed-tnb-lib-path.patch

@@ -1,5 +1,5 @@
 diff --git a/internal/bundled/noembed.go b/internal/bundled/noembed.go
-index 39b204b45..c2f3a1cf8 100644
+index 39b204b45..866f99caa 100644
 --- a/internal/bundled/noembed.go
 +++ b/internal/bundled/noembed.go
 @@ -2,11 +2,17 @@
@@ -20,15 +20,25 @@ index 39b204b45..c2f3a1cf8 100644
 
  	"github.com/microsoft/typescript-go/internal/tspath"
  	"github.com/microsoft/typescript-go/internal/vfs"
-@@ -29,10 +35,35 @@ var executableDir = sync.OnceValue(func() string {
+@@ -29,10 +35,45 @@ var executableDir = sync.OnceValue(func() string {
  	return tspath.GetDirectoryPath(exe)
  })
 
-+// getenvLive reads the process environ via libc so values set with setenv
-+// immediately before dlopen (Node process.env.TNB_LIB_PATH = ...) are visible.
-+// Go's os.Getenv may miss a key that was absent from the snapshot taken at
-+// runtime init depending on how/when the key was introduced.
++// getenvLive reads the live process environment for keys set immediately
++// before dlopen (Node process.env.TNB_LIB_PATH = ...).
++//
++// Two channels are needed:
++//   - os.Getenv: on Windows this resolves through the Win32 environment block,
++//     which Node's process.env write (SetEnvironmentVariableW) updates. It is
++//     the ONLY channel that works there — the CRT environ that libc getenv
++//     reads is initialized at process start and never sees that write.
++//   - libc getenv: on POSIX, Go's os.Getenv reads the runtime-init snapshot and
++//     can miss a libc setenv issued right before koffi.load; libc getenv reads
++//     the live CRT environ instead.
 +func getenvLive(key string) string {
++	if v := os.Getenv(key); v != "" {
++		return v
++	}
 +	ckey := C.CString(key)
 +	defer C.free(unsafe.Pointer(ckey))
 +	cval := C.getenv(ckey)

patches/typescript/overlay/src/compiler/tsgoChecker.ts

@@ -363,8 +363,10 @@ function loadBridgeDeps(): void {
             : "asyncpreemptoff=1";
     }
     // noembed: point tsgo at TNB lib/ before dlopen. Go may snapshot environ at
-    // runtime init, so noembed.go reads TNB_LIB_PATH via libc getenv (live), which
-    // sees this setenv as long as it happens before koffi.load below.
+    // runtime init; noembed.go's getenvLive therefore checks os.Getenv (Win32
+    // block — the only channel that sees SetEnvironmentVariableW on Windows)
+    // and libc getenv (live CRT environ for POSIX setenv) — both see this write
+    // as long as it happens before koffi.load below.
     // External non-empty override wins — do not clobber a pre-set path.
     if (!process.env.TNB_LIB_PATH) {
         process.env.TNB_LIB_PATH = path.join(packageRoot, "lib");