Fix build on OS X

sed on OS X doesn't handle \+

rts/ghc.mk

@@ -69,11 +69,13 @@ rts_H_FILES += $(DTRACEPROBES_H)
 endif
 
 # collect the -l and -L flags that we need to link the rts dyn lib.
+# Note that, as sed on OS X doesn't handle \+, we use [^ ][^ ]* rather
+# than [^ ]\+
 rts/libs.depend : $$(ghc-pkg_INPLACE)
 	"$(ghc-pkg_INPLACE)" --simple-output field rts extra-libraries \
-	  | sed -e 's/\([^ ]\+\)/-l\1/g' > $@
+	  | sed -e 's/\([^ ][^ ]*\)/-l\1/g' > $@
 	"$(ghc-pkg_INPLACE)" --simple-output field rts library-dirs \
-	  | sed -e 's/\([^ ]\+\)/-L\1/g' >> $@
+	  | sed -e 's/\([^ ][^ ]*\)/-L\1/g' >> $@
 
 
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