attempt to fix cygwin build

src/shogun/mathematics/Math.cpp

@@ -346,7 +346,7 @@ bool CMath::strtold(const char* str, floatmax_t* long_double_result)
 	char* endptr = buf.vector;
 
 // fall back to double on win32 / cygwin since strtold is undefined there
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
 	*long_double_result=::strtod(str, &endptr);
 #else
 	*long_double_result=::strtold(str, &endptr);