Create support sources folder if necessary.

Make sure the the xCodeSupport/Sources folder is always
present. The objj tool will fail if it's missing.

The Sources folder could be missing if it's not checked
into a repos for example.

Tools/XcodeCapp/TNXCodeCapp.m

@@ -460,14 +460,23 @@ - (BOOL)prepareXCodeSupportProject
         [PBXContent writeToFile:XCodeSupportPBXPath atomically:YES encoding:NSUTF8StringEncoding error:nil];
         DLog(@"PBX file adapted to the project");
 
-        DLog(@"Creating source folder %@", [XCodeSupportProjectSources path]);
-        [fm createDirectoryAtPath:[XCodeSupportProjectSources path] withIntermediateDirectories:YES attributes:nil error:nil];
+        [self createXcodeSupportProjectSourcesDirIfNecessary];
         return NO;
     }
 
+    [self createXcodeSupportProjectSourcesDirIfNecessary];
     return YES;
 }
 
+/*!
+ Create the xCodeSupport/Sources folder if necessary.
+ */
+- (void)createXcodeSupportProjectSourcesDirIfNecessary {
+    if ([fm fileExistsAtPath:[XCodeSupportProjectSources path]]) return;
+    DLog(@"Creating source folder %@", [XCodeSupportProjectSources path]);
+    [fm createDirectoryAtPath:[XCodeSupportProjectSources path] withIntermediateDirectories:YES attributes:nil error:nil];
+}
+
 /*!
  Initialize the creation of the .xCodeSupport project. This
  Operation is threaded