Fix path to windres on Win64

driver/ghci/ghc.mk

@@ -41,7 +41,7 @@ driver/ghci_dist_PROG_VER = ghci-$(ProjectVersion)$(exeext)
 INSTALL_BINS += driver/ghci/dist/build/tmp/$(driver/ghci_dist_PROG_VER)
 
 driver/ghci/ghci.res : driver/ghci/ghci.rc driver/ghci/ghci.ico
-	$(INPLACE_MINGW)/bin/windres --preprocessor="$(CPP) -xc -DRC_INVOKED" -o driver/ghci/ghci.res -i driver/ghci/ghci.rc -O coff
+	"$(WINDRES)" --preprocessor="$(CPP) -xc -DRC_INVOKED" -o driver/ghci/ghci.res -i driver/ghci/ghci.rc -O coff
 
 driver/ghci/dist/build/tmp/$(driver/ghci_dist_PROG_VER) : driver/ghci/dist/build/tmp/$(driver/ghci_dist_PROG)
 	"$(CP)" $< $@

mk/config.mk.in

@@ -622,6 +622,12 @@ ifeq "$(CrossCompiling)" "YES"
 SRC_HSC2HS_OPTS += --cross-compile
 endif
 
+ifeq "$(TARGETPLATFORM)" "i386-unknown-mingw32"
+WINDRES = $(INPLACE_MINGW)/bin/windres
+else ifeq "$(TARGETPLATFORM)" "x86_64-unknown-mingw32"
+WINDRES = $(INPLACE_MINGW)/bin/x86_64-w64-mingw32-windres
+endif
+
 #-----------------------------------------------------------------------------
 # Mingwex Library
 #