Fix -sMIN_NODE_VERSION=-1 -sENVIRONMENT=web to build without errors. (#25471)

Users might "double-disable" Node.js support by setting both
`-sENVIRONMENT=web` (no Node.js), and `-sMIN_NODE_VERSION=-1` (set Node
to unsupported).

But Emscripten complained about this not being allowed. Let this
combination pass.

Author: juj

test/test_other.py

@@ -14338,6 +14338,13 @@ def test_min_browser_version(self):
     err = self.expect_fail([EMCC, test_file('hello_world.c'), '-Wno-transpile', '-Werror', '-pthread', '-sMIN_FIREFOX_VERSION=65'])
     self.assertContained('emcc: error: MIN_FIREFOX_VERSION=65 is not compatible with pthreads (MIN_FIREFOX_VERSION=79 or above required)', err)
 
+  # Test that using two different ways to disable a target environment at the same time will not produce a warning.
+  def test_double_disable_environment(self):
+    self.run_process([EMCC, test_file('hello_world.c'), '-Werror', '-sENVIRONMENT=web', '-sMIN_NODE_VERSION=-1'])
+    self.run_process([EMCC, test_file('hello_world.c'), '-Werror', '-sENVIRONMENT=node', '-sMIN_FIREFOX_VERSION=-1'])
+    self.run_process([EMCC, test_file('hello_world.c'), '-Werror', '-sENVIRONMENT=node', '-sMIN_CHROME_VERSION=-1'])
+    self.run_process([EMCC, test_file('hello_world.c'), '-Werror', '-sENVIRONMENT=node', '-sMIN_SAFARI_VERSION=-1'])
+
   def test_signext_lowering(self):
     # Use `-v` to show the sub-commands being run by emcc.
     cmd = [EMCC, test_file('other/test_signext_lowering.c'), '-v']

tools/link.py

@@ -179,14 +179,14 @@ def setup_environment_settings():
   settings.ENVIRONMENT_MAY_BE_WORKER = not settings.ENVIRONMENT or 'worker' in settings.ENVIRONMENT
 
   if not settings.ENVIRONMENT_MAY_BE_NODE:
-    if 'MIN_NODE_VERSION' in user_settings:
+    if 'MIN_NODE_VERSION' in user_settings and settings.MIN_NODE_VERSION != feature_matrix.UNSUPPORTED:
       diagnostics.warning('unused-command-line-argument', 'ignoring MIN_NODE_VERSION because `node` environment is not enabled')
     settings.MIN_NODE_VERSION = feature_matrix.UNSUPPORTED
 
   if not (settings.ENVIRONMENT_MAY_BE_WEB or settings.ENVIRONMENT_MAY_BE_WEBVIEW):
     for browser in ('FIREFOX', 'SAFARI', 'CHROME'):
       key = f'MIN_{browser}_VERSION'
-      if key in user_settings:
+      if key in user_settings and settings[key] != feature_matrix.UNSUPPORTED:
         diagnostics.warning('unused-command-line-argument', 'ignoring %s because `web` and `webview` environments are not enabled', key)
       settings[key] = feature_matrix.UNSUPPORTED