From 887894aaef8fe7b436d48dd825dbcf5dfd4cf3ad Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Tue, 3 Jan 2017 03:55:29 +0000
Subject: [PATCH] Fix creating __generated_config on Windows

llvm-svn: 290853
---
 libcxx/include/CMakeLists.txt |  9 +++++--
 libcxx/utils/cat_files.py     | 46 +++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100755 libcxx/utils/cat_files.py

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 7b574353193d..0a9ed24a7f4c 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -35,8 +35,13 @@ if (LIBCXX_INSTALL_HEADERS)
     # Generate and install a custom __config header. The new header is created
     # by  prepending __config_site to the current __config header.
     add_custom_command(OUTPUT ${LIBCXX_BINARY_DIR}/__generated_config
-      COMMAND ${CMAKE_COMMAND} -E copy ${LIBCXX_BINARY_DIR}/__config_site ${LIBCXX_BINARY_DIR}/__generated_config
-      COMMAND ${UNIX_CAT} ${LIBCXX_SOURCE_DIR}/include/__config >> ${LIBCXX_BINARY_DIR}/__generated_config
+      COMMAND ${CMAKE_COMMAND} -E copy
+        ${LIBCXX_BINARY_DIR}/__config_site
+        ${LIBCXX_BINARY_DIR}/__generated_config
+      COMMAND ${PYTHON_EXECUTABLE} ${LIBCXX_SOURCE_DIR}/utils/cat_files.py
+        ${LIBCXX_BINARY_DIR}/__generated_config
+        ${LIBCXX_SOURCE_DIR}/include/__config
+        -o ${LIBCXX_BINARY_DIR}/__generated_config
       DEPENDS ${LIBCXX_SOURCE_DIR}/include/__config
               ${LIBCXX_BINARY_DIR}/__config_site
     )
diff --git a/libcxx/utils/cat_files.py b/libcxx/utils/cat_files.py
new file mode 100755
index 000000000000..83e7632f34ac
--- /dev/null
+++ b/libcxx/utils/cat_files.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+#===----------------------------------------------------------------------===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is dual licensed under the MIT and the University of Illinois Open
+# Source Licenses. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===##
+
+from argparse import ArgumentParser
+import sys
+
+def print_and_exit(msg):
+    sys.stderr.write(msg + '\n')
+    sys.exit(1)
+
+def main():
+    parser = ArgumentParser(
+        description="Concatenate two files into a single file")
+    parser.add_argument(
+        '-o', '--output', dest='output', required=True,
+        help='The output file. stdout is used if not given',
+        type=str, action='store')
+    parser.add_argument(
+        'files', metavar='files',  nargs='+',
+        help='The files to concatenate')
+
+    args = parser.parse_args()
+
+    if len(args.files) < 2:
+        print_and_exit('fewer than 2 inputs provided')
+    data = ''
+    for filename in args.files:
+        with open(filename, 'r') as f:
+            data += f.read()
+        if len(data) != 0 and data[-1] != '\n':
+            data += '\n'
+    assert len(data) > 0 and "cannot cat empty files"
+    with open(args.output, 'w') as f:
+        f.write(data)
+
+
+if __name__ == '__main__':
+    main()
+    sys.exit(0)