Support HIP (AcademySoftwareFoundation#498)

ADM's Heterogeneous-computing Interface for Portability API, similar
to CUDA.

See AcademySoftwareFoundation#462.

Signed-off-by: Cary Phillips <cary@ilm.com>

Author: cary-ilm

config/ImathConfig.h.in

@@ -98,10 +98,11 @@
 #endif
 
 //
-// Decorator that makes a function available for both CPU and GPU, when
-// compiling for Cuda.
+// Decorator that makes a function available for both CPU and GPU,
+// when compiling for Cuda or HIP (AMD's Heterogeneous-computing
+// Interface for Portability).
 //
-#ifdef __CUDACC__
+#if defined(__CUDACC__) || defined(__HIP__)
 #    define IMATH_HOSTDEVICE __host__ __device__
 #else
 #    define IMATH_HOSTDEVICE

src/Imath/ImathRoots.h

@@ -22,7 +22,9 @@
 
 /// @cond Doxygen_Suppress
 
-#ifdef __CUDACC__
+// If CUDA or HIP (AMD's Heterogeneous-computing Interface for
+// Portability), use the thrust complex library 
+#if defined(__CUDACC__) || defined(__HIP__)
 #    include <thrust/complex.h>
 #    define COMPLEX_NAMESPACE thrust
 #else