Removing unused iree/base/internal/main.h. (#11964)

All of the tools define their own main functions.
diff --git a/runtime/src/iree/base/internal/BUILD b/runtime/src/iree/base/internal/BUILD
index b8dfd7e..67ed31c 100644
--- a/runtime/src/iree/base/internal/BUILD
+++ b/runtime/src/iree/base/internal/BUILD
@@ -224,18 +224,6 @@
 )
 
 iree_runtime_cc_library(
-    name = "main",
-    srcs = [
-        "main_posix.c",
-        "main_win32.c",
-    ],
-    hdrs = ["main.h"],
-    deps = [
-        "//runtime/src/iree/base:core_headers",
-    ],
-)
-
-iree_runtime_cc_library(
     name = "path",
     srcs = ["path.c"],
     hdrs = ["path.h"],
diff --git a/runtime/src/iree/base/internal/CMakeLists.txt b/runtime/src/iree/base/internal/CMakeLists.txt
index d172026..2dfe704 100644
--- a/runtime/src/iree/base/internal/CMakeLists.txt
+++ b/runtime/src/iree/base/internal/CMakeLists.txt
@@ -235,19 +235,6 @@
 
 iree_cc_library(
   NAME
-    main
-  HDRS
-    "main.h"
-  SRCS
-    "main_posix.c"
-    "main_win32.c"
-  DEPS
-    iree::base::core_headers
-  PUBLIC
-)
-
-iree_cc_library(
-  NAME
     path
   HDRS
     "path.h"
diff --git a/runtime/src/iree/base/internal/main.h b/runtime/src/iree/base/internal/main.h
deleted file mode 100644
index 1321832..0000000
--- a/runtime/src/iree/base/internal/main.h
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2020 The IREE Authors
-//
-// Licensed under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-#ifndef IREE_BASE_INTERNAL_MAIN_H_
-#define IREE_BASE_INTERNAL_MAIN_H_
-
-#ifdef __cplusplus
-extern "C" {
-#endif  // __cplusplus
-
-int iree_main(int argc, char** argv);
-
-#ifdef __cplusplus
-}  // extern "C"
-#endif  // __cplusplus
-
-#endif  // IREE_BASE_INTERNAL_MAIN_H_
diff --git a/runtime/src/iree/base/internal/main_posix.c b/runtime/src/iree/base/internal/main_posix.c
deleted file mode 100644
index cf884a3..0000000
--- a/runtime/src/iree/base/internal/main_posix.c
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright 2020 The IREE Authors
-//
-// Licensed under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-#include "iree/base/internal/main.h"
-#include "iree/base/target_platform.h"
-
-#if defined(IREE_PLATFORM_ANDROID) || defined(IREE_PLATFORM_APPLE) || \
-    defined(IREE_PLATFORM_LINUX)
-
-int main(int argc, char** argv) { return iree_main(argc, argv); }
-
-#endif  // IREE_PLATFORM_*
diff --git a/runtime/src/iree/base/internal/main_win32.c b/runtime/src/iree/base/internal/main_win32.c
deleted file mode 100644
index 119ed19..0000000
--- a/runtime/src/iree/base/internal/main_win32.c
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright 2020 The IREE Authors
-//
-// Licensed under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-#include <stdlib.h>
-
-#include "iree/base/internal/main.h"
-#include "iree/base/target_platform.h"
-
-#if defined(IREE_PLATFORM_WINDOWS)
-
-#include <combaseapi.h>
-
-// Entry point when using /SUBSYSTEM:CONSOLE is the standard main().
-int main(int argc, char** argv) { return iree_main(argc, argv); }
-
-// Entry point when using /SUBSYSTEM:WINDOWS.
-// https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-winmain
-int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
-                   LPSTR lpCmdLine, int nShowCmd) {
-  // Setup COM on the main thread.
-  // NOTE: this may fail if COM has already been initialized - that's OK.
-  CoInitializeEx(NULL, COINIT_MULTITHREADED);
-
-  // Run standard main function.
-  // We use the MSVCRT __argc/__argv to get access to the standard argc/argv
-  // vs. using the flattened string passed to WinMain (that would require
-  // complex unicode splitting/etc).
-  // https://docs.microsoft.com/en-us/cpp/c-runtime-library/argc-argv-wargv
-  return iree_main(__argc, __argv);
-}
-
-#endif  // IREE_PLATFORM_WINDOWS