ENH: Improve Qt include path resolution macOS

Add specific framework path handling

Refactor include directory parsing to support multiple candidate paths
for headers and introduce macOS-specific logic for resolving
framework-relative header paths. Enhance generator flexibility and
robustness for cross-platform usage.

Push upstream fix via:
danmar/simplecpp#448

Author: hjmjohnson

generator/main.cpp

@@ -217,7 +217,20 @@ namespace
       QRegularExpression re("#define\\s+QTCORE_VERSION\\s+0x([0-9a-f]+)", QRegularExpression::CaseInsensitiveOption);
       for (const QString &includeDir: getIncludeDirectories(commandLineIncludes))
       {
-        QFileInfo fi(QDir(includeDir), "qtcoreversion.h");
+        std::list<std::string> candiate_paths;
+        candiate_paths.emplace_back("qtcoreversion.h");
+        candiate_paths.emplace_back("QtCore/qtcoreversion.h");
+        candiate_paths.emplace_back("QtCore.framework/Headers/qtcoreversion.h");
+        QFileInfo fi(QDir(includeDir), QString("qtcoreversion.h"));
+        for (const std::string &candidate : candiate_paths)
+        {
+          QFileInfo candidate_fi(QDir(includeDir), candidate.c_str());
+          if (candidate_fi.exists() && candidate_fi.isFile())
+          {
+              fi = candidate_fi;
+              break;
+          }
+        }
         if (fi.exists())
         {
           QString filePath = fi.absoluteFilePath();

generator/simplecpp/simplecpp.cpp

@@ -3116,13 +3116,40 @@ static std::string getIncludePathFileName(const std::string &includePath, const
     return path + header;
 }
 
+#ifdef __APPLE__
+static std::string get_apple_framework_relative_path(const std::string& header)
+{
+    std::string appleFrameworkHeader = {header};
+    // try the Framework path on Mac, if there is a path in front
+    // ### what about escaped slashes?
+    size_t slashPos = appleFrameworkHeader.find('/');
+    if (slashPos != std::string::npos)
+    {
+        constexpr auto framework_separator{ ".framework/Headers" };
+        appleFrameworkHeader.insert(slashPos, framework_separator);
+    }
+    return appleFrameworkHeader;
+}
+#endif // __APPLE__
+
 static std::string openHeaderIncludePath(std::ifstream &f, const simplecpp::DUI &dui, const std::string &header)
 {
     for (std::list<std::string>::const_iterator it = dui.includePaths.begin(); it != dui.includePaths.end(); ++it) {
         std::string simplePath = openHeader(f, getIncludePathFileName(*it, header));
         if (!simplePath.empty())
             return simplePath;
     }
+#ifdef __APPLE__
+    std::string appleFrameworkHeader = get_apple_framework_relative_path(header);
+    if (appleFrameworkHeader != header)
+    {
+        for (std::list<std::string>::const_iterator it = dui.includePaths.begin(); it != dui.includePaths.end(); ++it) {
+            std::string simplePath = openHeader(f, getIncludePathFileName(*it, appleFrameworkHeader));
+            if (!simplePath.empty())
+                return simplePath;
+        }
+    }
+#endif // __APPLE__
     return "";
 }
 

generator/simplecpp/simplecpp.h

@@ -39,6 +39,9 @@
 #endif
 
 namespace simplecpp {
+
+    std::string get_apple_framework_relative_path(const std::string& header);
+
     /** C code standard */
     enum cstd_t { CUnknown=-1, C89, C99, C11, C17, C23 };