fix linux configure

configure.ac

@@ -149,12 +149,11 @@ AM_CONDITIONAL([HAVE_NVML], [test -n "$with_nvml"])
 
 NVCC="nvcc"
 
-if test -n "$with_cuda"
+if test -n "$with_cuda" ; then
-then
   CUDA_INCLUDES="-I$with_cuda/include"
   CUDA_LIBS="-lcudart"
   CUDA_LDFLAGS="-L$with_cuda/lib$SUFFIX"
-  if test -x "$with_cuda/bin/nvcc"
+  if test -x "$with_cuda/bin/nvcc" ; then
     NVCC="$with_cuda/bin/nvcc"
   fi
 else