Build libssp as a DLL as well

This matches how it is normally available in GCC.

libssp-Makefile

@@ -6,11 +6,19 @@ AR = $(CROSS)ar
 
 CFLAGS = -O2 -Wall -Wundef -I$(SRC_PATH) -D_FORTIFY_SOURCE=0 -D__SSP_FORTIFY_LEVEL=0
 
-SOURCES = $(patsubst $(SRC_PATH)%,%,$(wildcard $(SRC_PATH)*.c))
+SOURCES = $(filter-out ssp-local.c, $(patsubst $(SRC_PATH)%,%,$(wildcard $(SRC_PATH)*.c)))
 OBJS = $(SOURCES:%.c=%.o)
 
+all: libssp.a libssp_nonshared.a libssp-0.dll
+
 libssp.a: $(OBJS)
 	$(AR) rcs $@ $+
 
+libssp-0.dll: $(OBJS)
+	$(CC) -shared -o $@ $+ -Wl,--out-implib,libssp.dll.a
+
+libssp_nonshared.a: ssp-local.o
+	$(AR) rcs $@ $+
+
 clean:
-	rm -f *.a *.o
+	rm -f *.a *.o *.dll