Correct OS arch within Cygwin emu

platformio/util.py

@@ -113,12 +113,18 @@ def singleton(cls):
 
 def get_systype():
     data = uname()
-    systype = data[0]
-    if "cygwin" in systype.lower():
-        systype = "windows"
-    if data[4]:
-        systype += "_" + data[4]
-    return systype.lower()
+    type_ = data[0].lower()
+    arch = data[4].lower() if data[4] else ""
+
+    # use native Windows binaries for Cygwin
+    if "cygwin" in type_:
+        if arch == "i686":
+            arch = "x86"
+        elif arch == "x86_64":
+            arch = "amd64"
+        type_ = "windows"
+
+    return "%s_%s" % (type_, arch) if arch else type_
 
 
 def pioversion_to_intstr():