Partially revert "Configure: do not include CC for generating CUDA code"

This reverts commit 0c4a54cce1.

Only omit CUDA compute flags for nvcc, not clang.

Makefile.in

@@ -11,7 +11,7 @@ CFLAGS        = @CFLAGS@ $(COMMON_FLAGS) -Werror=implicit-function-declaration -
 CPPFLAGS      = @CPPFLAGS@ -D_GNU_SOURCE
 CXXFLAGS      = @CXXFLAGS@ $(COMMON_FLAGS) -D_GNU_SOURCE
 MKDIR_P       = mkdir -p
-CUDA_FLAGS    = @CUDA_FLAGS@
+CUDA_FLAGS    = @CUDA_FLAGS@ @CUDA_COMPUTE_ARGS@
 LDFLAGS      =  @LDFLAGS@
 LIBS         += @LIBS@ @MATHLIBS@ -lm -pthread
 INC           = -Isrc -I$(srcdir) -I$(srcdir)/src -I$(srcdir)/test -Idxt_compress \

configure.ac

@@ -2071,6 +2071,7 @@ fi
 # 3) default system path (PATH, LD_LIBRARY_PATH, C_INCLUDE_PATH/CPATH)
 # 4) default CUDA path
 
+CUDA_COMPUTE_ARGS=""
 CUDA_COMPILER=""
 
 CUDA_INC=
@@ -2154,7 +2155,20 @@ AC_ARG_WITH(cuda-compiler,
               [CUDA_COMPILER="$withval"],
               [])
 
-HOST_CC_REPORT=" ("$(basename "$CUDA_COMPILER")
+HOST_CC_REPORT=" ("
+case "$CUDA_COMPILER" in
+	*nvcc*)
+		;;
+	*clang*)
+		CUDA_COMPUTE_ARGS="--cuda-gpu-arch=sm_30 --cuda-gpu-arch=sm_35"
+		;;
+	"")
+		;;
+	*)
+		AC_MSG_WARN([Unsupported cuda compiler $CUDA_COMPILER])
+		;;
+esac
+HOST_CC_REPORT="$HOST_CC_REPORT"$(basename "$CUDA_COMPILER")
 
 # CUDA host compiler
 AC_ARG_WITH(cuda-host-compiler,
@@ -2181,6 +2195,7 @@ AC_SUBST(CUDA_PATH)
 AC_SUBST(CUDA_LIB)
 AC_SUBST(CUDA_INC)
 AC_SUBST(CUDA_COMPILER)
+AC_SUBST(CUDA_COMPUTE_ARGS)
 
 # -------------------------------------------------------------------------------------------------
 # GPUJPEG