[mman] Fix static linkage. Fixes #2856.

ports/mman/CONTROL

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

ports/mman/mman-static.patch

@@ -0,0 +1,33 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 4696ad4..a72bbce 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -8,6 +8,10 @@ option (BUILD_TESTS "tests?" OFF)
+ set (headers mman.h)
+ set (sources mman.c)
+ 
++if(NOT BUILD_SHARED_LIBS)
++  add_definitions(-DMMANSHARED_EXPORT=)
++endif()
++
+ add_library (mman ${sources})
+ 
+ install (TARGETS mman RUNTIME DESTINATION bin
+diff --git a/mman.h b/mman.h
+index 4065bc6..435ea26 100644
+--- a/mman.h
++++ b/mman.h
+@@ -15,11 +15,13 @@
+ #include <_mingw.h>
+ #endif
+ 
++#if !defined(MMANSHARED_EXPORT)
+ #if defined(MMAN_LIBRARY)
+ #define MMANSHARED_EXPORT __declspec(dllexport)
+ #else
+ #define MMANSHARED_EXPORT __declspec(dllimport)
+ #endif
++#endif
+ 
+ /* Determine offset type */
+ #include <stdint.h>

ports/mman/portfile.cmake

@@ -8,16 +8,15 @@ vcpkg_from_github(
     HEAD_REF master
 )
 
-if(VCPKG_LIBRARY_LINKAGE STREQUAL "static")
-    set(ENABLE_SHARED OFF)
-else()
-    set(ENABLE_SHARED ON)
-endif()
+vcpkg_apply_patches(
+    SOURCE_PATH ${SOURCE_PATH}
+    PATCHES
+        ${CMAKE_CURRENT_LIST_DIR}/mman-static.patch
+)
 
 vcpkg_configure_cmake(
     SOURCE_PATH ${SOURCE_PATH}
-    OPTIONS
-        -DBUILD_SHARED_LIBS=${ENABLE_SHARED}
+    PREFER_NINJA
 )
 
 vcpkg_install_cmake()
@@ -25,4 +24,10 @@ vcpkg_install_cmake()
 file(INSTALL ${SOURCE_PATH}/README.md DESTINATION ${CURRENT_PACKAGES_DIR}/share/mman RENAME copyright)
 file(REMOVE_RECURSE ${CURRENT_PACKAGES_DIR}/debug/include)
 
+if(VCPKG_LIBRARY_LINKAGE STREQUAL "static")
+    file(READ ${CURRENT_PACKAGES_DIR}/include/sys/mman.h _contents)
+    string(REPLACE "__declspec(dllimport)" "" _contents "${_contents}")
+    file(WRITE ${CURRENT_PACKAGES_DIR}/include/sys/mman.h "${_contents}")
+endif()
+
 vcpkg_copy_pdbs()