external relocation entries in non-writable section?

[Rick Mann]

/usr/bin/ld: ../../target/lib/libdarbonapi.a(CFString.d.o) has external relocation entries in non-writable section (__TEXT,__text) for symbols:
___CFStringMakeConstantString

I'm not sure what this error message means (does it have to do with packaging it all in a static library? Don't see why...). In the library I've created, one of my modules (CFString.d) has this:

struct __CFString {};
typedef const __CFString*				CFStringRef;

extern (C)
CFStringRef
__CFStringMakeConstantString(char* cStr);

Other symbols seem to link just fine. I'm not sure what's different about this one.

TIA,
Rick