diff -r 427bf9130d12 -r c965548cb6f7 targets/toolchain_makefile.py
--- a/targets/toolchain_makefile.py	Thu Feb 17 10:11:04 2011 +0100
+++ b/targets/toolchain_makefile.py	Thu Feb 17 15:59:56 2011 +0100
@@ -14,7 +14,9 @@
         self.SetBuildPath(self.PluginsRootInstance._getBuildPath())
 
     def SetBuildPath(self, buildpath):
-        self.buildpath = buildpath
+        if self.buildpath != buildpath:
+            self.buildpath = buildpath
+            self.md5key = None
 
     def GetBinaryCode(self):
         return None
@@ -34,8 +36,9 @@
     def build(self):
         srcfiles= []
         cflags = []
+        wholesrcdata = "" 
+        print self.PluginsRootInstance.LocationCFilesAndCFLAGS
         for Location, CFilesAndCFLAGS, DoCalls in self.PluginsRootInstance.LocationCFilesAndCFLAGS:
-            wholesrcdata = "" 
             # Get CFiles list to give it to makefile
             for CFile, CFLAGS in CFilesAndCFLAGS:
                 CFileName = os.path.basename(CFile)
@@ -43,32 +46,39 @@
                 srcfiles.append(CFileName)
                 if CFLAGS not in cflags:
                     cflags.append(CFLAGS)
-                    
-            self.md5key = hashlib.md5(wholesrcdata).hexdigest()
-            props = self.PluginsRootInstance.GetProjectProperties()
-            self.md5key += '#'.join([props[key] for key in ['companyName',
-                                                            'projectName',
-                                                            'productName']])
-            self.md5key += '#' #+','.join(map(str,time.localtime()))
-            # Store new PLC filename based on md5 key
-            f = open(self._GetMD5FileName(), "w")
-            f.write(self.md5key)
-            f.close()
-        beremizcommand = {"src": ' '.join(srcfiles),
-                          "cflags": ' '.join(cflags),
-                          "md5": '"'+self.md5key+'"'
-                         }
-        
-        target = self.PluginsRootInstance.GetTarget().getcontent()["value"]
-        command = target.getCommand().split(' ') +\
-                  [target.getBuildPath()] +\
-                  [arg % beremizcommand for arg in target.getArguments().split(' ')] +\
-                  target.getRule().split(' ')
-        
-        # Call Makefile to build PLC code and link it with target specific code
-        status, result, err_result = ProcessLogger(self.PluginsRootInstance.logger,
-                                                   command).spin()
-        if status :
-            self.PluginsRootInstance.logger.write_error(_("C compilation of %s failed.\n"))
-            return False
-        return True
+                        
+        oldmd5 = self.md5key
+        self.md5key = hashlib.md5(wholesrcdata).hexdigest()
+        props = self.PluginsRootInstance.GetProjectProperties()
+        self.md5key += '#'.join([props[key] for key in ['companyName',
+                                                        'projectName',
+                                                        'productName']])
+        self.md5key += '#' #+','.join(map(str,time.localtime()))
+        # Store new PLC filename based on md5 key
+        f = open(self._GetMD5FileName(), "w")
+        f.write(self.md5key)
+        f.close()
+
+        if oldmd5 != self.md5key :
+            beremizcommand = {"src": ' '.join(srcfiles),
+                              "cflags": ' '.join(cflags),
+                              "md5": '"'+self.md5key+'"'
+                             }
+            
+            target = self.PluginsRootInstance.GetTarget().getcontent()["value"]
+            command = target.getCommand().split(' ') +\
+                      [target.getBuildPath()] +\
+                      [arg % beremizcommand for arg in target.getArguments().split(' ')] +\
+                      target.getRule().split(' ')
+            
+            # Call Makefile to build PLC code and link it with target specific code
+            status, result, err_result = ProcessLogger(self.PluginsRootInstance.logger,
+                                                       command).spin()
+            if status :
+                self.PluginsRootInstance.logger.write_error(_("C compilation of %s failed.\n"))
+                return False
+            return True
+        else :
+            self.PluginsRootInstance.logger.write(_("Source didn't change, no build.\n"))
+            return True
+