5 files changed, 46 insertions, 2 deletions
diff --git a/qmake/generators/makefile.cpp b/qmake/generators/makefile.cpp
index ac8bd8f9a7..83d38d1b14 100644
--- a/qmake/generators/makefile.cpp
+++ b/qmake/generators/makefile.cpp
@@ -456,6 +456,8 @@ MakefileGenerator::init()
     if (v["QMAKE_LINK_O_FLAG"].isEmpty())
         v["QMAKE_LINK_O_FLAG"].append("-o ");
 
+    setSystemIncludes(v["QMAKE_DEFAULT_INCDIRS"]);
+
     ProStringList &quc = v["QMAKE_EXTRA_COMPILERS"];
 
     //make sure the COMPILERS are in the correct input/output chain order
diff --git a/qmake/generators/makefiledeps.cpp b/qmake/generators/makefiledeps.cpp
index df37957f9b..e1fb42e0a4 100644
--- a/qmake/generators/makefiledeps.cpp
+++ b/qmake/generators/makefiledeps.cpp
@@ -345,6 +345,30 @@ bool QMakeSourceFileInfo::containsSourceFile(const QString &f, SourceFileType ty
     return false;
 }
 
+bool QMakeSourceFileInfo::isSystemInclude(const QString &name)
+{
+    if (QDir::isRelativePath(name)) {
+        // if we got a relative path here, it's either an -I flag with a relative path
+        // or an include file we couldn't locate. Either way, conclude it's not
+        // a system include.
+        return false;
+    }
+
+    for (int i = 0; i < systemIncludes.size(); ++i) {
+        // check if name is located inside the system include dir:
+        QDir systemDir(systemIncludes.at(i));
+        QString relativePath = systemDir.relativeFilePath(name);
+
+        // the relative path might be absolute if we're crossing drives on Windows
+        if (QDir::isAbsolutePath(relativePath) || relativePath.startsWith("../"))
+            continue;
+        debug_msg(5, "File/dir %s is in system dir %s, skipping",
+                  qPrintable(name), qPrintable(systemIncludes.at(i)));
+        return true;
+    }
+    return false;
+}
+
 char *QMakeSourceFileInfo::getBuffer(int s) {
     if(!spare_buffer || spare_buffer_size < s)
         spare_buffer = (char *)realloc(spare_buffer, spare_buffer_size=s);
diff --git a/qmake/generators/makefiledeps.h b/qmake/generators/makefiledeps.h
index ba55c36998..516abd4afd 100644
--- a/qmake/generators/makefiledeps.h
+++ b/qmake/generators/makefiledeps.h
@@ -78,6 +78,7 @@ private:
     SourceFiles *files, *includes;
     bool files_changed;
     QList<QMakeLocalFileName> depdirs;
+    QStringList systemIncludes;
 
     //sleezy buffer code
     char *spare_buffer;
@@ -98,6 +99,7 @@ protected:
     virtual QFileInfo findFileInfo(const QMakeLocalFileName &);
 
 public:
+
     QMakeSourceFileInfo(const QString &cachefile="");
     virtual ~QMakeSourceFileInfo();
 
@@ -108,11 +110,15 @@ public:
     inline void setDependencyMode(DependencyMode mode) { dep_mode = mode; }
     inline DependencyMode dependencyMode() const { return dep_mode; }
 
+    void setSystemIncludes(const ProStringList &list)
+    { systemIncludes = list.toQStringList(); }
+
     enum SourceFileType { TYPE_UNKNOWN, TYPE_C, TYPE_UI, TYPE_QRC };
     enum SourceFileSeek { SEEK_DEPS=0x01, SEEK_MOCS=0x02 };
     void addSourceFiles(const ProStringList &, uchar seek, SourceFileType type=TYPE_C);
     void addSourceFile(const QString &, uchar seek, SourceFileType type=TYPE_C);
     bool containsSourceFile(const QString &, SourceFileType type=TYPE_C);
+    bool isSystemInclude(const QString &);
 
     int included(const QString &file);
     QStringList dependencies(const QString &file);
diff --git a/qmake/generators/unix/unixmake2.cpp b/qmake/generators/unix/unixmake2.cpp
index 1444161ca9..8e18f69c03 100644
--- a/qmake/generators/unix/unixmake2.cpp
+++ b/qmake/generators/unix/unixmake2.cpp
@@ -125,10 +125,16 @@ UnixMakefileGenerator::writeMakeParts(QTextStream &t)
         t << " -I" << pwd;
     }
     {
+        QString isystem = var("QMAKE_CFLAGS_ISYSTEM");
         const ProStringList &incs = project->values("INCLUDEPATH");
         for(int i = 0; i < incs.size(); ++i) {
             ProString inc = escapeFilePath(incs.at(i));
-            if(!inc.isEmpty())
+            if (inc.isEmpty())
+                continue;
+
+            if (!isystem.isEmpty() && isSystemInclude(inc.toQString()))
+                t << ' ' << isystem << ' ' << inc;
+            else
                 t << " -I" << inc;
         }
     }
diff --git a/qmake/generators/win32/mingw_make.cpp b/qmake/generators/win32/mingw_make.cpp
index 1aeaef1d23..6d5764f59c 100644
--- a/qmake/generators/win32/mingw_make.cpp
+++ b/qmake/generators/win32/mingw_make.cpp
@@ -321,12 +321,18 @@ void MingwMakefileGenerator::writeIncPart(QTextStream &t)
         t << "-I" << pwd << " ";
     }
 
+    QString isystem = var("QMAKE_CFLAGS_ISYSTEM");
     const ProStringList &incs = project->values("INCLUDEPATH");
     for (ProStringList::ConstIterator incit = incs.begin(); incit != incs.end(); ++incit) {
         QString inc = (*incit).toQString();
         inc.replace(QRegExp("\\\\$"), "");
         inc.replace(QRegExp("\""), "");
-        t << "-I" << quote << inc << quote << " ";
+
+        if (!isystem.isEmpty() && isSystemInclude(inc))
+            t << isystem << ' ';
+        else
+            t << "-I";
+        t << quote << inc << quote << " ";
     }
     t << "-I" << quote << specdir() << quote
       << endl;