Index: src/plugins/compilergcc/compilerCYGWIN.cpp
===================================================================
--- src/plugins/compilergcc/compilerCYGWIN.cpp    (revision 7711)
+++ src/plugins/compilergcc/compilerCYGWIN.cpp    (working copy)
@@ -35,9 +35,11 @@
 {
     CompilerMINGW::Reset();
 
-    m_Programs.C = _T("gcc.exe");
-    m_Programs.CPP = _T("g++.exe");
-    m_Programs.LD = _T("g++.exe");
+    // NOTE: Cygwin's gcc.exe is a file link and
+    // is not a good default name for running via cmd.exe
+    m_Programs.C = _T("gcc-3.exe");
+    m_Programs.CPP = _T("g++-3.exe");
+    m_Programs.LD = _T("g++-3.exe");
     m_Programs.DBG = _T("gdb.exe");
     m_Programs.LIB = _T("ar.exe");
     m_Programs.WINDRES = _T("windres.exe");
@@ -48,24 +50,68 @@
     m_Options.AddOption(_("Do not use cygwin specific functionality"), _T("-mno-cygwin"), _("General"));
 }
 
+bool isNormalFileNotSymlink(const wxString& filename){
+    if (wxFileExists(filename)){
+        wxFile aFile(filename);
+        if (aFile.IsOpened()){
+            char buffer[10]={0};
+            aFile.Read(buffer,10);
+            if (memcmp("!<symlink>", buffer, 10) != 0){
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
 AutoDetectResult CompilerCYGWIN::AutoDetectInstallationDir()
 {
-    m_MasterPath = _T("C:\\Cygwin"); // just a guess
+    AutoDetectResult ret = adrGuessed;
+    wxString tempMasterPath = _T("C:\\Cygwin"); // just a guess
+    m_MasterPath = tempMasterPath;
+    bool validInstallationDir = false;
 
     // look in registry for Cygwin
 
     wxRegKey key; // defaults to HKCR
-    key.SetName(_T("HKEY_LOCAL_MACHINE\\Software\\Cygnus Solutions\\Cygwin\\mounts v2\\/"));
+    key.SetName(_T("HKEY_LOCAL_MACHINE\\Software\\Cygwin\\setup"));
     if (key.Exists() && key.Open(wxRegKey::Read))
     {
-        // found; read it
-        key.QueryValue(_T("native"), m_MasterPath);
+        // found CygWin version 1.7 or newer; read it
+        key.QueryValue(_T("rootdir"), tempMasterPath);
+        if (wxDirExists(
+                tempMasterPath + wxFILE_SEP_PATH +
+                _T("bin"))
+        ){
+                validInstallationDir = true;
+        }
     }
-    AutoDetectResult ret = wxFileExists(m_MasterPath + wxFILE_SEP_PATH +
-                                        _T("bin") + wxFILE_SEP_PATH +
-                                        m_Programs.C)
-                            ? adrDetected
-                            : adrGuessed;
+    if (!validInstallationDir){
+        key.SetName(_T("HKEY_LOCAL_MACHINE\\Software\\Cygnus Solutions\\Cygwin\\mounts v2\\/"));
+        if (key.Exists() && key.Open(wxRegKey::Read))
+        {
+            // found CygWin version 1.5 or older; read it
+            key.QueryValue(_T("native"), tempMasterPath);
+            if (wxDirExists(
+                    tempMasterPath + wxFILE_SEP_PATH +
+                    _T("bin")
+                )
+            ){
+                validInstallationDir = true;
+            }
+        }
+    }
+
+    if (validInstallationDir){
+        wxString cProgramDir = tempMasterPath + wxFILE_SEP_PATH +
+            _T("bin") + wxFILE_SEP_PATH;
+        wxString cProgramFullname = cProgramDir + m_Programs.C;
+        if (isNormalFileNotSymlink(cProgramFullname)){
+            m_MasterPath = tempMasterPath;
+            ret = adrDetected;
+        }
+    }
+
     return ret;
 }