View Compilation Error

In file included from 0_0_18886142_2821.cpp:6:0:
GCC4.9.2/x86_64-w64-mingw32/include/math.h:205:25: error: conflicting declaration of 'int abs(int)' with 'C' linkage
   int __cdecl abs(int _X);
                         ^
0_0_18886142_2821.cpp:2:5: note: previous declaration with 'C++' linkage
 int abs(int x)
     ^