Recognize MSYS compiler as MINGW compiler (capstone-engine#1290)

Makefile

@@ -302,7 +302,7 @@ CFLAGS := $(CFLAGS:-fPIC=)
 # On Windows we need the shared library to be executable
 else
 # mingw?
-IS_MINGW := $(shell $(CC) --version 2>/dev/null | grep -i mingw | wc -l)
+IS_MINGW := $(shell $(CC) --version 2>/dev/null | grep -i "\(mingw\|MSYS\)" | wc -l)
 ifeq ($(IS_MINGW),1)
 EXT = dll
 AR_EXT = lib