Improve wasapi backend UWP support (#853)

* Improve wasapi, support uwp build

* Fix compile errors

* [UWP] Support ReadALConfig from app roaming

* [UWP] Post disconnect event when default device changed

* [UWP] Fix appveyor ci

* [WIN32] Default device change notification support

* Fix warnings

* Add event to notify the app when the default device changes

- Event type: AL_EVENT_TYPE_DEFAULT_DEVICE_CHANGED_SOFT=0x19A7
- Event callback parameters:
  void _onALSoftEvent(ALenum eventType,
                    ALuint object, // dataFlow: 0(render), 1(capture)
                    ALuint param, // 0
                    ALsizei length, // 0
                    const ALchar* message, // Default device changed:<deviceId>
                    void* userParam);

* Fix warnings

* Fire default device changed event in mixerProc thread

* Fix compile warning

* [UWP] Improve cmake

* Revert changes

* Notify default device change by system event callback

* Revert insignificant change

* Remove duplicate call

3 files changed, 22 insertions, 6 deletions

diff --git a/core/async_event.h b/core/async_event.h
index c049fa02..f1ca0c7b 100644
--- a/core/async_event.h
+++ b/core/async_event.h
@@ -15,7 +15,6 @@ enum class AsyncEnableBits : uint8_t {
     SourceState,
     BufferCompleted,
     Disconnected,
-
     Count
 };
 
diff --git a/core/helpers.cpp b/core/helpers.cpp
index 58cc74e5..f9de25cf 100644
--- a/core/helpers.cpp
+++ b/core/helpers.cpp
@@ -3,6 +3,11 @@
 
 #include "helpers.h"
 
+#if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#endif
+
 #include <algorithm>
 #include <cerrno>
 #include <cstdarg>
@@ -40,7 +45,7 @@ const PathNamePair &GetProcBinary()
 {
     static std::optional<PathNamePair> procbin;
     if(procbin) return *procbin;
-
+#if !defined(ALSOFT_UWP)
     auto fullpath = std::vector<WCHAR>(256);
     DWORD len{GetModuleFileNameW(nullptr, fullpath.data(), static_cast<DWORD>(fullpath.size()))};
     while(len == fullpath.size())
@@ -58,7 +63,16 @@ const PathNamePair &GetProcBinary()
     fullpath.resize(len);
     if(fullpath.back() != 0)
         fullpath.push_back(0);
-
+#else
+    auto exePath               = __wargv[0];
+    if (!exePath)
+    {
+        ERR("Failed to get process name: error %lu\n", GetLastError());
+        procbin.emplace();
+        return *procbin;
+    }
+    std::vector<WCHAR> fullpath{exePath, exePath + wcslen(exePath) + 1};
+#endif
     std::replace(fullpath.begin(), fullpath.end(), '/', '\\');
     auto sep = std::find(fullpath.rbegin()+1, fullpath.rend(), '\\');
     if(sep != fullpath.rend())
@@ -84,7 +98,7 @@ void DirectorySearch(const char *path, const char *ext, std::vector<std::string>
 
     std::wstring wpath{utf8_to_wstr(pathstr.c_str())};
     WIN32_FIND_DATAW fdata;
-    HANDLE hdl{FindFirstFileW(wpath.c_str(), &fdata)};
+    HANDLE hdl{FindFirstFileExW(wpath.c_str(), FindExInfoStandard, &fdata, FindExSearchNameMatch, NULL, 0)};
     if(hdl == INVALID_HANDLE_VALUE) return;
 
     const auto base = results->size();
@@ -97,7 +111,6 @@ void DirectorySearch(const char *path, const char *ext, std::vector<std::string>
         str += wstr_to_utf8(fdata.cFileName);
     } while(FindNextFileW(hdl, &fdata));
     FindClose(hdl);
-
     const al::span<std::string> newlist{results->data()+base, results->size()-base};
     std::sort(newlist.begin(), newlist.end());
     for(const auto &name : newlist)
@@ -149,6 +162,7 @@ std::vector<std::string> SearchDataFiles(const char *ext, const char *subdir)
     std::replace(path.begin(), path.end(), '/', '\\');
     DirectorySearch(path.c_str(), ext, &results);
 
+#if !defined(ALSOFT_UWP)
     /* Search the local and global data dirs. */
     static const int ids[2]{ CSIDL_APPDATA, CSIDL_COMMON_APPDATA };
     for(int id : ids)
@@ -165,17 +179,20 @@ std::vector<std::string> SearchDataFiles(const char *ext, const char *subdir)
 
         DirectorySearch(path.c_str(), ext, &results);
     }
+#endif
 
     return results;
 }
 
 void SetRTPriority(void)
 {
+#if !defined(ALSOFT_UWP)
     if(RTPrioLevel > 0)
     {
         if(!SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL))
             ERR("Failed to set priority level for thread\n");
     }
+#endif
 }
 
 #else
diff --git a/core/uiddefs.cpp b/core/uiddefs.cpp
index 244c01a5..833150f5 100644
--- a/core/uiddefs.cpp
+++ b/core/uiddefs.cpp
@@ -24,7 +24,7 @@ DEFINE_GUID(IID_IAudioClient,         0x1cb9ad4c, 0xdbfa, 0x4c32, 0xb1,0x78, 0xc
 DEFINE_GUID(IID_IAudioRenderClient,   0xf294acfc, 0x3146, 0x4483, 0xa7,0xbf, 0xad,0xdc,0xa7,0xc2,0x60,0xe2);
 DEFINE_GUID(IID_IAudioCaptureClient,  0xc8adbd64, 0xe71e, 0x48a0, 0xa4,0xde, 0x18,0x5c,0x39,0x5c,0xd3,0x17);
 
-#ifdef HAVE_WASAPI
+#if defined(HAVE_WASAPI) && !defined(ALSOFT_UWP)
 #include <wtypes.h>
 #include <devpropdef.h>
 #include <propkeydef.h>