message: openssl: use nmake as BUILD_COMMAND for Windows
diff: @@ -36,7 +36,9 @@ elseif(MSVC)
  openssl
  URL https://www.openssl.org/source/openssl-${OPENSSL_VERSION}.tar.gz
  PREFIX openssl
  - CONFIGURE_COMMAND perl <SOURCE_DIR>/Configure VC-WIN32 --prefix=${CMAKE_INSTALL_PREFIX} no-shared
  + CONFIGURE_COMMAND perl <SOURCE_DIR>/Configure VC-WIN64A --prefix=${CMAKE_INSTALL_PREFIX} no-shared
  + BUILD_COMMAND set MAKEFLAGS= && nmake
  + INSTALL_COMMAND set MAKEFLAGS= && nmake install
  )
  else()
  ExternalProject_add(
  