Add windows/README.md back with development section.

Author: haydenroche5

windows/README.md

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+# Building on Windows
+
+wolfEngine has Visual Studio support for FIPS 140-2, FIPS Ready, and non-FIPS
+builds. All expect the following directory structure:
+
+```
+.
+├── openssl
+├── wolfEngine
+└── wolfssl
+```
+
+The build will not work unless the directories are named as above.
+
+## OpenSSL
+
+Follow the instructions in the OpenSSL `INSTALL` file. The list of commands to
+run are:
+
+```
+$ perl Configure { VC-WIN32 | VC-WIN64A | VC-WIN64I | VC-CE }
+$ nmake clean # This command needs to be run if OpenSSL has previously been
+built in this directory with a different configuration.
+$ nmake
+```
+
+## wolfSSL
+
+The wolfSSL FIPS module performs an integrity check over the code and read only
+data contents of itself during the FIPS self-test. This requires that the
+module be assembled in a specific order, with the object files wolfcrypt_first.o
+and wolfcrypt_last.o marking the beginning and end of the FIPS module,
+respectively. The only way we have found to reliably ensure this ordering on
+Windows is by building wolfSSL as a DLL. As such, even static builds of
+wolfEngine (i.e. the "Debug" and "Release" configurations) will use wolfSSL as a
+DLL. All wolfEngine Visual Studio configurations also use OpenSSL as a DLL.
+
+### FIPS 140-2
+
+First, replace the contents of `IDE\WIN10\user_settings.h` in wolfSSL with the
+contents of `windows\fips_140_2\user_settings.h` from wolfEngine. Then, compile
+wolfSSL using `IDE\WIN10\wolfssl-fips.sln`.
+
+### FIPS Ready
+
+First, replace the contents of `IDE\WIN10\user_settings.h` in wolfSSL with the
+contents of `windows\fips_ready\user_settings.h` from wolfEngine. Then, compile
+wolfSSL using `IDE\WIN10\wolfssl-fips.sln`.
+
+### Non-FIPS
+
+First, replace the contents of `IDE\WIN\user_settings.h` in wolfSSL with the
+contents of `windows\non_fips\user_settings.h` from wolfEngine. Then, compile
+wolfSSL using `wolfssl64.sln`.
+
+## wolfEngine
+
+The wolfEngine "test" project copies the OpenSSL and wolfSSL DLLs into the test
+output directory. If you want to skip the OpenSSL step and use system supplied
+versions of OpenSSL, delete the OpenSSL DLL copy command under the test
+project's properties:
+
+```
+Properties -> Configuration Properties -> Build Events -> Post-Build Event ->
+Command Line
+```
+
+There is currently no official support for using OpenSSL as a static library
+with wolfEngine.
+
+### FIPS 140-2
+
+Build wolfEngine using `windows\wolfEngine.sln`. Select one of the 4 FIPS 140-2
+configurations (e.g. DLL Debug FIPS 140-2). Run the test suite by right-clicking
+on the "test" project in the Solution Explorer > Debug > Start New Instance. You
+are likely to encounter this error message:
+
+```
+in FIPS callback, ok = 0, err = -203
+message = In Core Integrity check FIPS error
+hash = 550122FD59F12AFA94F1B0D95AB361FF03E3EB8708C68974C36D6571524B675C
+In core integrity hash check failure, copy above hash
+into verifyCore[] in wolfSSL's (NOT wolfEngine) fips_test.c and rebuild
+ERR: Failed to find engine!
+```
+
+As mentioned earlier, part of wolfSSL's FIPS self-test is an integrity check
+of the FIPS module. At startup, the self-test computes an HMAC of the code and
+read-only data of the FIPS module and compares the result to an expected value
+compiled into the library. If these don't match, the FIPS module enters an error
+state and cannot be used. The wolfEngine test program will print the above error
+message in this case. If this happens, you should take the hash value printed
+out and replace the `verifyCore` value in wolfSSL's `wolfcrypt\src\fips_test.c`
+with it. Rebuild wolfSSL, rebuild wolfEngine, and run the wolfEngine tests
+again. The integrity check should pass this time.
+
+### FIPS Ready
+
+Build wolfEngine using `windows\wolfEngine.sln`. Select one of the 4 FIPS Ready
+configurations (e.g. DLL Debug FIPS Ready). Run the test suite by right-clicking
+on the "test" project in the Solution Explorer > Debug > Start New Instance. The
+FIPS self-test noted above for FIPS 140-2 applies to FIPS Ready, too, so you
+will need to update the expected hash value accordingly.
+
+### Non-FIPS
+
+Build wolfEngine using `windows\wolfEngine.sln`. Select one of the 4 non-FIPS
+configurations (e.g. DLL Debug Non-FIPS) Run the test suite by right-clicking on
+the "test" project in the Solution Explorer > Debug > Start New Instance.
+
+# Development
+
+The build options for the various configurations are all held in property sheets
+in the `windows\props\` directory. If you need to add a new build option (e.g.
+a macro or compiler option), you should add it to the most general property
+sheet possible. For example, if you are adding a compiler option that should be
+applied to all debug configurations, add it to debug.props. If you are adding a
+macro that should only be applied when building the test project with wolfSSL
+FIPS (Ready or 140-2) and a debug configuration, add it to
+debug_fips_test.props. Do NOT add properties directly to wolfEngine.vcxproj or
+test.vcxproj unless absolutely necessary, but this will likely never be the
+case.