Treat .bc files as source files

This matches the behaviour of clang, and means that `.ll` and `.bc`
files get treated similarly.  The modified test here no longer applies
since we no longer run `nm` on linker inputs.

ChangeLog.md

@@ -21,6 +21,9 @@ See docs/process.md for more on how version tagging works.
 3.1.52 (in development)
 -----------------------
 - The `--default-obj-ext` command line flag was removed. (#20917)
+- emcc will not treat files with the `.bc` extension as source files.  These
+  will get compiled to object files before being passed to the linker.  This
+  matches the behaviour of clang.
 
 3.1.51 - 12/13/23
 -----------------

emcc.py

@@ -65,7 +65,7 @@
 SPECIAL_ENDINGLESS_FILENAMES = [os.devnull]
 C_ENDINGS += SPECIAL_ENDINGLESS_FILENAMES # consider the special endingless filenames like /dev/null to be C
 
-SOURCE_ENDINGS = C_ENDINGS + CXX_ENDINGS + OBJC_ENDINGS + OBJCXX_ENDINGS + ['.ll', '.S']
+SOURCE_ENDINGS = C_ENDINGS + CXX_ENDINGS + OBJC_ENDINGS + OBJCXX_ENDINGS + ['.bc', '.ll', '.S']
 ASSEMBLY_ENDINGS = ['.s']
 HEADER_ENDINGS = ['.h', '.hxx', '.hpp', '.hh', '.H', '.HXX', '.HPP', '.HH']
 

test/test_other.py

@@ -12622,18 +12622,9 @@ def test_no_main_with_PROXY_TO_PTHREAD(self):
     self.assertContained('crt1_proxy_main.o: undefined symbol: main', err)
 
   def test_archive_bad_extension(self):
-    # Regression test for https://github.com/emscripten-core/emscripten/issues/14012
-    # where llvm_nm_multiple would be confused by archives names like object files.
-    create_file('main.c', '''
-    #include <sys/socket.h>
-    int main() {
-       return (int)(long)&accept;
-    }
-    ''')
-
-    self.run_process([EMCC, '-c', 'main.c'])
-    self.run_process([EMAR, 'crs', 'libtest.bc', 'main.o'])
-    self.run_process([EMCC, 'libtest.bc', 'libtest.bc'])
+    self.run_process([EMCC, '-c', test_file('hello_world.c')])
+    self.run_process([EMAR, 'crs', 'libtest.bc', 'hello_world.o'])
+    err = self.expect_fail([EMCC, 'libtest.bc'])
 
   def test_split_dwarf_implicit_compile(self):
     # Verify that the dwo file is generated in the current working directory, even when implicitly