gcc: Compile test programs with $STARPU_CUDA_CPPFLAGS.

* gcc-plugin/tests/run-test.in (%cuda-cppflags): New variable.
  (%default-cflags): Use it.

gcc-plugin/tests/run-test.in

@@ -70,12 +70,17 @@ exec "${GUILE-@GUILE@}" -l "$0"    \
 (define %builddir "@builddir@")
 (define %gcc "@CC@")
 
+(define %cuda-cppflags
+  (string-tokenize "@STARPU_CUDA_CPPFLAGS@"))
+
 (define %default-cflags
   `("-I" ,%srcdir
     "-I" ,(string-append %srcdir "/../../include")
     "-I" ,(string-append %builddir "/../../include")
     "-I" ,(string-append %builddir "/../..")
 
+    ,@%cuda-cppflags
+
     ;; Unfortunately `libtool --mode=execute' doesn't help here, so hard-code
     ;; the real file name.
     ,(string-append "-fplugin=" %builddir "/../src/.libs/starpu.so")