libdispatch: use blocks runtime from libobjc2

Using patch from:
swiftlang/swift-corelibs-libdispatch#534

Author: triplef

patches/libdispatch-own-blocksruntime.patch

@@ -0,0 +1,86 @@
+From f49931127fe7673931c6550194c593923b2fbfd7 Mon Sep 17 00:00:00 2001
+From: Niels Grewe <[email protected]>
+Date: Sun, 24 Nov 2019 08:24:56 +0100
+Subject: [PATCH 1/2] build: search for system-supplied libBlocksRuntime
+
+This allows the user to provide a version of libBlocksRuntime on
+systems other than Darwin.
+
+https://github.com/apple/swift-corelibs-libdispatch/pull/534
+---
+ CMakeLists.txt                        | 2 ++
+ cmake/modules/FindBlocksRuntime.cmake | 2 ++
+ src/CMakeLists.txt                    | 3 +--
+ 3 files changed, 5 insertions(+), 2 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 75c419c13..458c1cd95 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -115,6 +115,8 @@ endif()
+ 
+ find_package(LibRT)
+ 
++find_package(BlocksRuntime QUIET)
++
+ check_function_exists(_pthread_workqueue_init HAVE__PTHREAD_WORKQUEUE_INIT)
+ check_function_exists(getprogname HAVE_GETPROGNAME)
+ check_function_exists(mach_absolute_time HAVE_MACH_ABSOLUTE_TIME)
+diff --git a/cmake/modules/FindBlocksRuntime.cmake b/cmake/modules/FindBlocksRuntime.cmake
+index 111a5d634..eb3f539e9 100644
+--- a/cmake/modules/FindBlocksRuntime.cmake
++++ b/cmake/modules/FindBlocksRuntime.cmake
+@@ -45,4 +45,6 @@ if(BlocksRuntime_FOUND)
+                             INTERFACE_INCLUDE_DIRECTORIES
+                               ${BlocksRuntime_INCLUDE_DIR})
+   endif()
++else()
++  set(BlocksRuntime_INCLUDE_DIR "${PROJECT_SOURCE_DIR}/src/BlocksRuntime")
+ endif()
+diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
+index c88b430de..e2da3aaa8 100644
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -1,5 +1,4 @@
+-
+-if(NOT CMAKE_SYSTEM_NAME STREQUAL Darwin)
++if(NOT BlocksRuntime_FOUND)
+   add_subdirectory(BlocksRuntime)
+ endif()
+ 
+
+From 18ef62595830ce69ccfc9353457e5efd1b64f54e Mon Sep 17 00:00:00 2001
+From: Niels Grewe <[email protected]>
+Date: Sun, 24 Nov 2019 21:54:36 +0100
+Subject: [PATCH 2/2] build: Remove a superfluous include path
+
+---
+ cmake/modules/FindBlocksRuntime.cmake | 2 --
+ tests/CMakeLists.txt                  | 3 ---
+ 2 files changed, 5 deletions(-)
+
+diff --git a/cmake/modules/FindBlocksRuntime.cmake b/cmake/modules/FindBlocksRuntime.cmake
+index eb3f539e9..111a5d634 100644
+--- a/cmake/modules/FindBlocksRuntime.cmake
++++ b/cmake/modules/FindBlocksRuntime.cmake
+@@ -45,6 +45,4 @@ if(BlocksRuntime_FOUND)
+                             INTERFACE_INCLUDE_DIRECTORIES
+                               ${BlocksRuntime_INCLUDE_DIR})
+   endif()
+-else()
+-  set(BlocksRuntime_INCLUDE_DIR "${PROJECT_SOURCE_DIR}/src/BlocksRuntime")
+ endif()
+diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
+index a27603559..0af5aac87 100644
+--- a/tests/CMakeLists.txt
++++ b/tests/CMakeLists.txt
+@@ -78,9 +78,6 @@ function(add_unit_test name)
+     # to reduce probability of test failures due to machine load.
+     target_compile_options(${name} PRIVATE -DLENIENT_DEADLINES=1)
+   endif()
+-  target_include_directories(${name}
+-                             SYSTEM BEFORE PRIVATE
+-                               "${BlocksRuntime_INCLUDE_DIR}")
+   if("${CMAKE_C_SIMULATE_ID}" STREQUAL "MSVC")
+     target_compile_options(${name} PRIVATE -Xclang -fblocks)
+     target_compile_options(${name} PRIVATE /W3 -Wno-deprecated-declarations)

phases/18-libdispatch.bat

@@ -18,12 +18,15 @@ cd "%BUILD_DIR%" || exit /b 1
 
 echo.
 echo ### Running cmake
-:: CXX and linker flags below are to produce PDBs for release builds
+:: CXX and linker flags below are to produce PDBs for release builds.
+:: BlocksRuntime parameters provided to use blocks runtime from libobjc2 with libdispatch-own-blocksruntime.patch.
 cmake .. %CMAKE_OPTIONS% ^
   -D BUILD_SHARED_LIBS=YES ^
   -D INSTALL_PRIVATE_HEADERS=YES ^
   -D CMAKE_CXX_FLAGS_RELWITHDEBINFO="/Zi" ^
   -D CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO="/INCREMENTAL:NO /DEBUG /OPT:REF /OPT:ICF" ^
+  -D BlocksRuntime_INCLUDE_DIR=%INSTALL_PREFIX%\include ^
+  -D BlocksRuntime_LIBRARIES=%INSTALL_PREFIX%\lib\objc.lib ^
   || exit /b 1
 
 echo.
@@ -34,10 +37,8 @@ echo.
 echo ### Installing
 ninja install || exit /b 1
 
-:: Install PDB files
-xcopy /Y /F BlocksRuntime.pdb "%INSTALL_PREFIX%\lib\"
+:: Install PDB file
 xcopy /Y /F dispatch.pdb "%INSTALL_PREFIX%\lib\"
 
-:: Move DLLs from bin to lib directory.
-move /Y "%INSTALL_PREFIX%\bin\BlocksRuntime.dll" "%INSTALL_PREFIX%\lib\"
+:: Move DLL from bin to lib directory.
 move /Y "%INSTALL_PREFIX%\bin\dispatch.dll" "%INSTALL_PREFIX%\lib\"