Don't pass -Xlinker flags to clang when compiling

This avoids a warning about unused linker flags.

emcc.py

@@ -949,6 +949,7 @@ def phase_compile_inputs(options, state, newargs, input_files):
     compiler.insert(0, config.COMPILER_WRAPPER)
 
   compile_args = newargs
+
   system_libs.ensure_sysroot()
 
   def get_language_mode(args):
@@ -1016,13 +1017,25 @@ def get_clang_command_asm():
 
   # In COMPILE_AND_LINK we need to compile source files too, but we also need to
   # filter out the link flags
+  compile_args = []
 
   def is_link_flag(flag):
     if flag in ('-nostdlib', '-nostartfiles', '-nolibc', '-nodefaultlibs', '-s'):
       return True
     return flag.startswith(('-l', '-L', '-Wl,', '-z'))
 
-  compile_args = [a for a in compile_args if a and not is_link_flag(a)]
+  skip = False
+  for arg in newargs:
+    if skip:
+      skip = False
+      continue
+    if is_link_flag(arg):
+      continue
+    if arg == '-Xlinker':
+      skip = True
+      continue
+    compile_args.append(arg)
+
   linker_inputs = []
   seen_names = {}
 

test/test_other.py

@@ -11946,6 +11946,11 @@ def test_linker_flags_unused(self):
     err = self.run_process([EMCC, test_file('hello_world.c'), '-c', '-lbar'], stderr=PIPE).stderr
     self.assertContained("warning: -lbar: 'linker' input unused [-Wunused-command-line-argument]", err)
 
+    # Check that we don't see these input unused errors for linker flags (i.e. ensure that we
+    # don't pass them to clang when compiling internally.
+    err = self.run_process([EMCC, test_file('hello_world.c'), '-Wl,-static', '-Xlinker', '-static'], stderr=PIPE).stderr
+    self.assertNotContained("input unused", err)
+
   def test_linker_input_unused(self):
     self.run_process([EMCC, '-c', test_file('hello_world.c')])
     err = self.run_process([EMCC, 'hello_world.o', '-c', '-o', 'out.o'], stderr=PIPE).stderr