third-party: remove msvc-compat/unistd.h (#10465)

This was upstreamed into unibilium.

third-party/cmake/BuildUnibilium.cmake

@@ -14,9 +14,6 @@ if(WIN32)
     CONFIGURE_COMMAND ${CMAKE_COMMAND} -E copy
       ${CMAKE_CURRENT_SOURCE_DIR}/cmake/UnibiliumCMakeLists.txt
       ${DEPS_BUILD_DIR}/src/unibilium/CMakeLists.txt
-      COMMAND ${CMAKE_COMMAND} -E copy
-        ${CMAKE_CURRENT_SOURCE_DIR}/msvc-compat/unistd.h
-        ${DEPS_BUILD_DIR}/src/unibilium/msvc-compat/unistd.h
       COMMAND ${CMAKE_COMMAND} ${DEPS_BUILD_DIR}/src/unibilium
         -DCMAKE_INSTALL_PREFIX=${DEPS_INSTALL_DIR}
         # Pass toolchain

third-party/cmake/UnibiliumCMakeLists.txt

@@ -18,10 +18,6 @@ else()
 endif()
 target_compile_definitions(unibilium PUBLIC TERMINFO_DIRS=${TERMINFO_DIRS})
 
-if(MSVC)
-  target_include_directories(unibilium PUBLIC ${PROJECT_SOURCE_DIR}/msvc-compat)
-endif()
-
 include(GNUInstallDirs)
 install(TARGETS unibilium
   PUBLIC_HEADER

third-party/msvc-compat/unistd.h

@@ -1,10 +0,0 @@
-#ifndef GUARD_UNIBILIUM_UNISTD_H_
-#define GUARD_UNIBILIUM_UNISTD_H_
-
-#ifdef  _WIN64
-typedef unsigned __int64    ssize_t;
-#else
-typedef _W64 unsigned int   ssize_t;
-#endif
-
-#endif