feat(qt): add fallback mkspec support for different platforms

- Introduce fallbackmkspec variable to handle mkspec selection
- Set platform-specific fallback mkspec values:
  - macosx: macx-clang
  - linux: linux-g++
  - windows: win32-msvc
  - mingw: win32-g++
  - android: android-clang
  - wasm: wasm-emscripten
- Implement conditional logic to use qt.mkspec when available,
  otherwise fall back to platform-specific mkspec
- Maintain backward compatibility with existing mkspec usage

1 files changed, 12 insertions, 1 deletions

diff --git a/xmake/rules/qt/load.lua b/xmake/rules/qt/load.lua
index 53b5a1ba2..252e6db5b 100644
--- a/xmake/rules/qt/load.lua
+++ b/xmake/rules/qt/load.lua
@@ -414,7 +414,7 @@ function main(target, opt)
     end
 
     -- add includedirs, linkdirs
-    _add_includedirs(target, path.join(qt.mkspecsdir, qt.mkspec))
+    local fallbackmkspec = ""
     if target:is_plat("macosx") then
         target:add("frameworks", "DiskArbitration", "IOKit", "CoreFoundation", "CoreGraphics", "OpenGL")
         target:add("frameworks", "Carbon", "Foundation", "AppKit", "Security", "SystemConfiguration")
@@ -435,15 +435,18 @@ function main(target, opt)
             target:set("frameworks", frameworks)
         end
         _add_includedirs(target, qt.includedir)
+        fallbackmkspec = "macx-clang"
         target:add("linkdirs", qt.libdir)
     elseif target:is_plat("linux") then
         target:set("frameworks", nil)
         _add_includedirs(target, qt.includedir)
+        fallbackmkspec = "linux-g++"
         target:add("rpathdirs", qt.libdir)
         target:add("linkdirs", qt.libdir)
     elseif target:is_plat("windows") then
         target:set("frameworks", nil)
         _add_includedirs(target, qt.includedir)
+        fallbackmkspec = "win32-msvc"
         target:add("linkdirs", qt.libdir)
         target:add("syslinks", "ws2_32", "gdi32", "ole32", "advapi32", "shell32", "user32", "opengl32", "imm32", "winmm", "iphlpapi")
         -- for debugger, https://github.com/xmake-io/xmake-vscode/issues/225
@@ -467,16 +470,19 @@ function main(target, opt)
         else
             _add_includedirs(target, qt.includedir)
         end
+        fallbackmkspec = "win32-g++"
         target:add("linkdirs", qt.libdir)
         target:add("syslinks", "mingw32", "ws2_32", "gdi32", "ole32", "advapi32", "shell32", "user32", "iphlpapi")
     elseif target:is_plat("android") then
         target:set("frameworks", nil)
         _add_includedirs(target, qt.includedir)
+        fallbackmkspec = "android-clang"
         target:add("rpathdirs", qt.libdir)
         target:add("linkdirs", qt.libdir)
     elseif target:is_plat("wasm") then
         target:set("frameworks", nil)
         _add_includedirs(target, qt.includedir)
+        fallbackmkspec = "wasm-emscripten"
         target:add("rpathdirs", qt.libdir)
         target:add("linkdirs", qt.libdir)
         -- add prebuilt object files in qt sdk.
@@ -510,6 +516,11 @@ function main(target, opt)
             target:add("shflags", "-s EXPORTED_RUNTIME_METHODS=[\"UTF16ToString\",\"stringToUTF16\"]")
         end
     end
+    if qt.mkspec then
+        _add_includedirs(target, path.join(qt.mkspecsdir, qt.mkspec))
+    else
+        _add_includedirs(target, path.join(qt.mkspecsdir, fallbackmkspec))
+    end
 
     -- is gui application?
     if opt.gui then