Notice that with the SDK root, it adds
-L/Developer/SDKs/MacOSX10.4u.sdk/usr/lib/gcc/darwin/gdc.0.17
(which doesn't actually exist, but that's beside the point).
I'm using a D-language plugin made by someone else, and I thought that it must indicate somewhere to include that directory, but I can't find anything in its files that matches. I want to adjust things so it actually looks in the right place, but I don't know where this stuff comes from.
The root cause of all this: if I link on the command line using something like:
$(GDC) -framework Carbon -framework CoreFoundation -g -o $(APPTRGT)/Contents/MacOS/$(EXNAME) $(OBJ) $(APIOBJ)
It links just fine. But the gdc call inside Xcode fails to include a couple of libraries implicitly included by the gdc command line (libgphobos, the std D library and libgcc_eh.a, exception handling for gcc).
So, I'm trying to figure out how to get Xcode (or gdc when called by Xcode) to "do the right thing" without having to explicitly include the libraries in the project (they're not required for Carbon app projects, for example).