Fixing CUDA compilation

m4/ax_cuda.m4

@@ -56,16 +56,25 @@ AS_IF([test "x$NVCC_EXIST" = "xno"],[],[
 
           # If $build_cpu contains "_64", append "64" to CUDA_LIBS
           AS_IF([echo $build_cpu | grep -q "_64"],
-                [CUDA_LIBS+="64"])
-                
+                [
+                 AS_IF([ test -d {CUDA_LIBS}lib64 ], [ CUDA_LIBS+="64" ])
+                 AS_IF([ ! command -v bumblebee >/dev/null  ], [ 
+                                                               CUDA_LIBS+=" -L/usr/lib64/nvidia-bumblebee/ "
+                                                             ])
+                 AS_IF([ test -d /usr/local/cuda/lib64  ], [ CUDA_LIBS+=" -L/usr/local/cuda/lib64 "  ],
+                       [
+                        AS_IF([ test -d /usr/local/cuda/lib ],[ CUDA_LIBS+=" -L/usr/local/cuda/lib  "  ])
+                       ])
+                ])
+
           # Append " -lcuda -lcudart" to CUDA_LIBS
           CUDA_LIBS+=" -lcuda -lcudart"
 
           # Make variables available in Makefile.am
-          AC_SUBST(CUDA_CFLAGS)
-          AC_SUBST(CUDA_LIBS)
+          AC_SUBST([CUDA_CFLAGS])
+          AC_SUBST([CUDA_LIBS])
           echo $NVCC
-          AC_SUBST(NVCC)
+          AC_SUBST([NVCC])
           AC_DEFINE([NVCC],[],[NVCC compiling])
 ])dnl