Use option "-sf" for the AIX "ln" command.

Author: xingxue-ibm

tests/run-make/libs-through-symlinks/Makefile

@@ -3,10 +3,20 @@ include ../tools.mk
 
 # ignore-windows
 
+# The option -n for the AIX ln command has a different purpose than it does
+# on Linux. On Linux, the -n option is used to treat the destination path as
+# normal file if it is a symbolic link to a directory, which is the default
+# behavior of the AIX ln command.
+ifeq ($(UNAME),AIX)
+LN_FLAGS := -sf
+else
+LN_FLAGS := -nsf
+endif
+
 NAME := $(shell $(RUSTC) --print file-names foo.rs)
 
 all:
 	mkdir -p $(TMPDIR)/outdir
 	$(RUSTC) foo.rs -o $(TMPDIR)/outdir/$(NAME)
-	ln -nsf outdir/$(NAME) $(TMPDIR)
+	ln $(LN_FLAGS) outdir/$(NAME) $(TMPDIR)
 	RUSTC_LOG=rustc_metadata::loader $(RUSTC) bar.rs