diff --git a/README.MacOS b/README.MacOS
index 266d981b0..b069bbf8f 100644
--- a/README.MacOS
+++ b/README.MacOS
@@ -57,9 +57,19 @@ source or binary distributions.  (Also, make sure to use GNU tar if/when
 *building* such distributions!) The version of tar that comes with Mac OS X
 10.3.3 doesn't have this problem.
 
-The linker on OS X may also have problems linking large executables in debug
-grades.  This affects all versions of ld that we have tested and there is
-currently no known workaround.
+On PowerPC machines, the linker may have problems linking large executables
+(particularly in debug grades; technically when the program requires a branch
+larger than +/- 32 MB). It complains about relocation displacements being too
+large. The only known workaround for this problem is to replace the
+system-provided versions of crt1.o (Darwin module 'Csu') and crt2.o (part of
+gcc) with versions that are compiled with the gcc options `-mlongcall' and (if
+using gcc < ~ 3.4) `-mlong-branch'. C code generated by the Mercury compiler
+will also need to be compiled with the above options. This can be achieved by
+adding:
+
+    EXTRA_CFLAGS=-mlongcall -mlong-branch
+
+to your Mercury.options or Mmakefile.
 
 -----------------------------------
 Known bugs and unsupported features