Includes <cmath> or <math.h> by __cplusplus in hip_complex.h

include/hip/hcc_detail/hip_complex.h

@@ -24,7 +24,15 @@ THE SOFTWARE.
 #define HIP_INCLUDE_HIP_HCC_DETAIL_HIP_COMPLEX_H
 
 #include "hip/hcc_detail/hip_vector_types.h"
+
+// TODO: Clang has a bug which allows device functions to call std functions
+// when std functions are introduced into default namespace by using statement.
+// math.h may be included after this bug is fixed.
+#if __cplusplus
 #include <cmath>
+#else
+#include "math.h"
+#endif
 
 #if __cplusplus
 #define COMPLEX_ADD_OP_OVERLOAD(type)                                                              \