Refactor clang check to use startswith method

Author: waruqi

xmake/modules/core/tools/gcc.lua

@@ -867,7 +867,7 @@ function nf_pmheader(self, pcheaderfile, opt)
     if self:kind() == "mm" then
         local target = opt.target
         local pcoutputfile = target:pcoutputfile("m")
-        if self:name() == "clang" then
+        if self:name():startswith("clang") then
             return {"-include", pcheaderfile, "-include-pch", pcoutputfile}
         else
             return {"-I", path.directory(pcoutputfile), "-include", path.filename(pcheaderfile)}
@@ -880,7 +880,7 @@ function nf_pmxxheader(self, pcheaderfile, opt)
     if self:kind() == "mxx" then
         local target = opt.target
         local pcoutputfile = target:pcoutputfile("mxx")
-        if self:name() == "clang" then
+        if self:name():startswith("clang") then
             return {"-include", pcheaderfile, "-include-pch", pcoutputfile}
         else
             return {"-I", path.directory(pcoutputfile), "-include", path.filename(pcheaderfile)}