Add autoconf code to locate dlltool on Windows

configure.ac

@@ -428,6 +428,21 @@ FP_ARG_WITH_PATH_GNU_PROG([LD], [ld])
 LdCmd="$LD"
 AC_SUBST([LdCmd])
 
+dnl ** Check for dlltool on Windows
+dnl --------------------------------------------------------------
+case $HostOS_CPP in
+cygwin32|mingw32)
+	AC_PATH_PROG(DlltoolCmd,dlltool)
+	if test -z "$DlltoolCmd"; then
+	  echo "Can't find dlltool in your path, can't make DLLs."
+	  exit 1
+	fi
+	;;
+*)
+	AC_SUBST(DlltoolCmd,"")
+	;;
+esac
+
 dnl ** Which nm to use?
 dnl --------------------------------------------------------------
 FP_ARG_WITH_PATH_GNU_PROG([NM], [nm])

mk/config.mk.in

@@ -550,6 +550,7 @@ SRC_HSC2HS_OPTS += $(foreach d,$(GMP_INCLUDE_DIRS),-I$(d))
 # Mingwex Library
 #
 HaveLibMingwEx	= @HaveLibMingwEx@
+DLLTOOL			= @DlltoolCmd@
 
 #-----------------------------------------------------------------------------
 # Flex (currently unused, could be moved to glafp-utils)

rts/ghc.mk

@@ -118,7 +118,7 @@ ifneq "$$(findstring dyn, $1)" ""
 $$(rts_$1_LIB) : $$(rts_$1_OBJS) rts/libs.depend
 	"$$(RM)" $$(RM_OPTS) $$@
   ifeq "$(HOSTPLATFORM)" "i386-unknown-mingw32"
-	dlltool -d rts/win32/libHSbase.def -l rts/dist/build/win32/libHSbase.so.a
+	"$$(DLLTOOL)" -d rts/win32/libHSbase.def -l rts/dist/build/win32/libHSbase.so.a
 	"$$(rts_dist_HC)" -shared -dynamic -dynload deploy \
 	  -no-auto-link-packages `cat rts/libs.depend` $$(rts_$1_OBJS) rts/dist/build/win32/libHSbase.so.a -o $$@
   else