Merge branch 'bugfix/unix_makefile_build_on_windows' into 'master'

CMake: Fix build error when using Windows command line and MinGW generator

See merge request idf/esp-idf!3997

components/mbedtls/CMakeLists.txt

@@ -18,13 +18,51 @@ endfunction()
 # Needed to for include_next includes to work from within mbedtls
 include_directories("${COMPONENT_PATH}/port/include")
 
-# Needed in order to workaround issue with improper conversion to native path
-# when building on MSYS2. This ensures that when building on MSYS, Unix style 
-# paths are used.
-set(msystem $ENV{MSYSTEM})
+# Workaround issue with creating symbolic links due to issues with native
+# path conversion (TO_NATIVE_PATH). The following summarizes what CMake invocations
+# this workaround is for:
+#
+# 1. CMake from command line + Ninja = No errors
+# 2. CMake from command line + MinGW Makefiles = Forward slash for paths, mklink mistakes path for a switch
+# 3. CMake from MSYS + Ninja = No errors
+# 4. CMake from MSYS + Unix Makefiles/MSYS Makefiles = Forward slash for paths, mklink mistakes path for a switch
+#
+# There are references to the issue in case (2) and (4) in https://github.com/ARMmbed/mbedtls/issues/1496,
+# https://cmake.org/pipermail/cmake/2006-July/010193.html, and https://cmake.org/Bug/view.php?id=5939.
+#
+# This workaround is meant to circumvent logic inside link_to_source() function in mbedtls/mbedtls/CMakeLists.txt.
+if(CMAKE_HOST_WIN32)
+    set(msystem $ENV{MSYSTEM})
+    if(MSYS OR msystem)
+        # Solves case (4). When in MSYS environment, instead opt to use the Unix equivalent of mklink.
+        set(CMAKE_HOST_UNIX 1)
+    else()
+        # Solves case (2). When invoked from command line, create the symbolic links ahead of link_to_source() invocations
+        # using a 'hybrid' path format resilient intermediary - in this case a Python wrapper for mklink. This is more unweildy
+        # than necessary, since string(REPLACE "/" "\\" ... does not actually work.
+        set(target_links "mbedtls/include/mbedtls"
+                        "mbedtls/scripts")
+        foreach(target_link ${target_links})
+            file(TO_NATIVE_PATH ${CMAKE_CURRENT_BINARY_DIR}/${target_link} link)
+            file(TO_NATIVE_PATH ${COMPONENT_PATH}/${target_link} target)
 
-if(MSYS OR msystem)
-    set(CMAKE_HOST_UNIX 1)
+            if(NOT EXISTS ${link})
+                if (IS_DIRECTORY ${target})
+                    set(command ${PYTHON} ${COMPONENT_PATH}/mklink.py /j ${link} ${target})
+                else()
+                    set(command ${PYTHON} ${COMPONENT_PATH}/mklink.py /h ${link} ${target})
+                endif()
+
+                execute_process(COMMAND ${command}
+                    RESULT_VARIABLE result
+                    ERROR_VARIABLE output)
+
+                if (NOT ${result} EQUAL 0)
+                    message(FATAL_ERROR "Could not create symbolic link for: ${target} --> ${output}")
+                endif()
+            endif()
+        endforeach()
+    endif()
 endif()
 
 # Import mbedtls library targets

components/mbedtls/mklink.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+#
+# Wrapper for symbolic link creation on Windows that works around issues
+# with native path conversion. See the component CMakeLists.txt for more details.
+#
+# Copyright 2018 Espressif Systems (Shanghai) PTE LTD
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http:#www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import os
+import argparse
+import subprocess
+
+parser = argparse.ArgumentParser()
+parser.add_argument("type")
+parser.add_argument("link")
+parser.add_argument("target")
+
+args = parser.parse_args()
+
+link = os.path.abspath(args.link)
+target = os.path.abspath(args.target)
+
+try:
+    os.makedirs(os.path.dirname(link))
+except WindowsError:
+    pass
+
+mklink_cmd = ["mklink", args.type, link, target]
+
+subprocess.call(mklink_cmd, shell=True)