Add cmake option to enable win32 fibers

CMakeLists.txt

@@ -135,6 +135,10 @@ cmake_dependent_option( KICAD_WIN32_DPI_AWARE
     "Turn on DPI awareness for Windows builds only"
     OFF "WIN32" OFF )
 
+cmake_dependent_option( KICAD_WIN32_CONTEXT_WINFIBER
+    "Use win32 fibers for libcontext"
+    OFF "WIN32" OFF )
+
 option( KICAD_USE_EGL
     "Build KiCad with EGL backend support for Wayland."
     OFF )
@@ -219,6 +223,13 @@ perform_feature_checks()
 # Setup the compiler warnings
 include( ${CMAKE_MODULE_PATH}/Warnings.cmake )
 
+if( KICAD_WIN32_CONTEXT_WINFIBER )
+    set(LIBCONTEXT_USE_WINFIBER true)
+    add_compile_definitions(LIBCONTEXT_USE_WINFIBER)
+else()
+    set(LIBCONTEXT_USE_WINFIBER false)
+endif()
+
 if( WIN32 )
     # define UNICODE and_UNICODE definition on Windows. KiCad uses unicode.
     # Both definitions are required

thirdparty/libcontext/CMakeLists.txt

@@ -16,6 +16,7 @@ list(APPEND LIBCONTEXT_SOURCES
 if( MSVC )
     enable_language(ASM_MASM)
 
+    if( NOT LIBCONTEXT_USE_WINFIBER )
         if ( NOT CMAKE_SIZEOF_VOID_P EQUAL 8 )
             list(APPEND LIBCONTEXT_SOURCES
                 make_i386_ms_pe_masm.asm
@@ -27,6 +28,9 @@ if( MSVC )
                 jump_x86_64_ms_pe_masm.asm
                 )
         endif()
+    else()
+        add_compile_definitions(LIBCONTEXT_USE_WINFIBER)
+    endif()
 endif()
 
 add_library( libcontext OBJECT

thirdparty/libcontext/libcontext.cpp

@@ -1398,10 +1398,15 @@ intptr_t LIBCONTEXT_CALL_CONVENTION jump_fcontext( fcontext_t* ofc, fcontext_t n
 
 void LIBCONTEXT_CALL_CONVENTION release_fcontext( fcontext_t ctx )
 {
+    if( ctx == nullptr )
+		return;
+
 	if( fiberParams.find( ctx ) != fiberParams.end() )
 	{
 		fiberParams.erase( ctx );
 	}
+
+	DeleteFiber( ctx );
 }