Fix compile error ‘isnan’ was not declared in this scope

xfa/fxbarcode/utils.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef XFA_FXBARCODE_UTILS_H_
 #define XFA_FXBARCODE_UTILS_H_
 
 #include "core/fxcrt/include/fx_basic.h"
 
 typedef CFX_MapPtrTemplate<void*, int32_t> CFX_PtrToInt32;
 FX_BOOL BC_FX_ByteString_Replace(CFX_ByteString& dst,
                                  uint32_t first,
                                  uint32_t last,
                                  int32_t count,
                                  FX_CHAR c);
 void BC_FX_ByteString_Append(CFX_ByteString& dst, int32_t count, FX_CHAR c);
 void BC_FX_ByteString_Append(CFX_ByteString& dst, const CFX_ByteArray& ba);
 
 #if (_FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN64_)
 #include <limits>
 #elif(_FX_OS_ == _FX_MACOSX_ || _FX_OS_ == _FX_LINUX_DESKTOP_ || \
       _FX_OS_ == _FX_IOS_)
 #include <limits.h>
 #endif
 #if (_FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN64_)
 #define FXSYS_isnan(x) _isnan(x)
-#elif(_FX_OS_ == _FX_MACOSX_ || _FX_OS_ == _FX_IOS_)
+#elif(_FX_OS_ == _FX_MACOSX_ || _FX_OS_ == _FX_IOS_ || \
+      _FX_OS_ == _FX_LINUX_DESKTOP_ || _FX_OS_ == _FX_ANDROID_)
 #include <cmath>
 #define FXSYS_isnan(x) std::isnan(x)
-#elif(_FX_OS_ == _FX_LINUX_DESKTOP_ || _FX_OS_ == _FX_ANDROID_)
-#include <math.h>
-#define FXSYS_isnan(x) isnan(x)
 #endif
 #if (_FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN64_)
 #define FXSYS_nan() (std::numeric_limits<float>::quiet_NaN())
 #elif(_FX_OS_ == _FX_MACOSX_ || _FX_OS_ == _FX_LINUX_DESKTOP_ || \
       _FX_OS_ == _FX_IOS_ || _FX_OS_ == _FX_ANDROID_)
 #define FXSYS_nan() NAN
 #endif
 enum BCFORMAT {
   BCFORMAT_UNSPECIFY = -1,
   BCFORMAT_CODABAR,
@@ skipping 127 matching lines @@
 #define THREE_DIGIT_PLUS_DIGIT_DATA_LENGTH_SIZE 57
 #define FOUR_DIGIT_DATA_LENGTH_SIZE 17
 #define BC_EXCEPTION_CHECK_ReturnVoid(e) \
   if (e != BCExceptionNO)                \
     return;
 #define BC_EXCEPTION_CHECK_ReturnValue(e, v) \
   if (e != BCExceptionNO)                    \
     return v;
 
 #endif  // XFA_FXBARCODE_UTILS_H_