properly target windows 2000 in mingw build + allows to build for windows ME now as well

Makefile

@@ -1,15 +1,16 @@
 -include config.mk
 
-TARGET    = ddraw.dll
-LDFLAGS   = -Wl,--enable-stdcall-fixup -s -static -shared
-CFLAGS    = -Iinc -O2 -march=i486 -Wall -std=c99
-LIBS      = -lgdi32 -lwinmm -ldbghelp -lole32
+TARGET   ?= ddraw.dll
+
+LDFLAGS  ?= -Wl,--enable-stdcall-fixup -s -static -shared
+CFLAGS   ?= -Iinc -O2 -Wall -std=c99
+LIBS      = -lgdi32 -lwinmm -ldbghelp -lole32 -lMsimg32
 
 COMMIT   := $(shell git describe --match=NeVeRmAtCh --always --dirty || echo UNKNOWN)
 BRANCH   := $(shell git rev-parse --abbrev-ref HEAD || echo UNKNOWN)
 
-CMDTEST  := $(shell echo \"\")
-ifeq ($(CMDTEST),\"\")
+ECHOTEST := $(shell echo \"\")
+ifeq ($(ECHOTEST),\"\")
 	# Windows
 	HASH     := \#
 	ECOMMIT  := $(shell echo $(HASH)define GIT_COMMIT "$(COMMIT)" > inc/git.h)
@@ -20,13 +21,17 @@ else
 	EBRANCH  := $(shell echo "#define GIT_BRANCH" \"$(BRANCH)\" >> inc/git.h)
 endif
 
-CC        = i686-w64-mingw32-gcc
-WINDRES  ?= i686-w64-mingw32-windres
-
 ifdef DEBUG
 	CFLAGS   += -D _DEBUG -D _DEBUG_X
 endif
 
+ifdef _WIN32_WINNT
+	CFLAGS   += -march=i486 -D _WIN32_WINNT=$(_WIN32_WINNT)
+endif
+
+CC        = i686-w64-mingw32-gcc
+WINDRES  ?= i686-w64-mingw32-windres
+
 SRCS     := $(wildcard src/*.c) $(wildcard src/*/*.c) res.rc
 OBJS     := $(addsuffix .o, $(basename $(SRCS)))