[mman] Move header to mman/sys/mman.h to avoid tricking other libraries

ports/mman/CONTROL

@@ -1,3 +1,3 @@
 Source: mman
-Version: git-f5ff813-1
+Version: git-f5ff813-2
 Description: A light implementation of the mmap functions for MinGW.

ports/mman/portfile.cmake

@@ -21,6 +21,10 @@ vcpkg_configure_cmake(
 
 vcpkg_install_cmake()
 
+file(MAKE_DIRECTORY ${CURRENT_PACKAGES_DIR}/include/mman)
+file(RENAME ${CURRENT_PACKAGES_DIR}/include/sys ${CURRENT_PACKAGES_DIR}/include/mman/sys)
+
+file(COPY ${CMAKE_CURRENT_LIST_DIR}/usage DESTINATION ${CURRENT_PACKAGES_DIR}/share/mman)
 file(INSTALL ${SOURCE_PATH}/README.md DESTINATION ${CURRENT_PACKAGES_DIR}/share/mman RENAME copyright)
 file(REMOVE_RECURSE ${CURRENT_PACKAGES_DIR}/debug/include)
 

ports/mman/usage

@@ -0,0 +1,4 @@
+The mman.h header deployed by mman is placed in mman/sys/mman.h to avoid accidental inclusion.
+
+    find_path(MMAN_DIR NAMES sys/mman.h PATH_SUFFIXES mman)
+    target_include_directories(main PRIVATE ${MMAN_DIR})