Modified Makefile to be able to compile on Cygwin

Makefile

@@ -1,8 +1,19 @@
 CC=gcc
 CFLAGS=-Wall -O3
+UNAME_S := $(shell uname -s)
+SO_PREFIX=lib
+SO_EXT=.so
+
+ifeq ($(findstring CYGWIN,$(UNAME_S)), CYGWIN)
+  SO_PREFIX=cyg
+  SO_EXT=.dll
+endif
+
+PICRIN_LIB=$(SO_PREFIX)picrin$(SO_EXT)
 
 all: build-debug run
 
+release: CFLAGS += -DDEBUG=0
 release: build
 
 build-debug: CFLAGS += -g -DDEBUG=1
@@ -12,16 +23,17 @@ build: build-lib build-main
 
 build-main:
 	$(CC) $(CFLAGS) tools/main.c -o bin/picrin -I./include -L./lib -lpicrin -lreadline
+	cp lib/$(PICRIN_LIB) bin/
 
 build-lib:
 	cd src; \
 	  yacc -d parse.y; \
 	  lex scan.l
-	$(CC) $(CFLAGS) -shared src/*.c -o lib/libpicrin.so -I./include -I./extlib
+	$(CC) $(CFLAGS) -shared src/*.c -o lib/$(PICRIN_LIB) -I./include -I./extlib
 
 clean:
 	rm -f src/y.tab.c src/y.tab.h src/lex.yy.c
-	rm -f lib/libpicrin.so
+	rm -f lib/$(PICRIN_LIB)
 	rm -f bin/picrin
 
 run: