fix passing FXT_LDFLAGS

configure.ac

@@ -913,6 +913,7 @@ if test x$use_fxt = xyes; then
 	if test x$use_fxt_from_system = xno; then
 		FXT_CFLAGS="-I$fxtdir/include/ "
 		FXT_LDFLAGS="-L$fxtdir/lib/"
+		AC_ARG_VAR(FXT_LDFLAGS)
 		FXT_LIBS="-lfxt"
 	else
 	    PKG_CHECK_MODULES([FXT],  [fxt])

src/Makefile.am

@@ -52,7 +52,7 @@ libstarpu_@STARPU_EFFECTIVE_VERSION@_la_CPPFLAGS = -I$(top_srcdir)/include/ -DBU
 
 libstarpu_@STARPU_EFFECTIVE_VERSION@_la_CFLAGS = $(GLOBAL_AM_CFLAGS) $(HWLOC_CFLAGS) $(STARPU_CUDA_CPPFLAGS) $(STARPU_OPENCL_CPPFLAGS) $(FXT_CFLAGS)
 libstarpu_@STARPU_EFFECTIVE_VERSION@_la_LIBADD = -lm $(HWLOC_LIBS) $(STARPU_CUDA_LDFLAGS) $(STARPU_OPENCL_LDFLAGS) $(FXT_LIBS) $(STARPU_GLPK_LDFLAGS)
-libstarpu_@STARPU_EFFECTIVE_VERSION@_la_LDFLAGS = $(ldflags) -no-undefined									\
+libstarpu_@STARPU_EFFECTIVE_VERSION@_la_LDFLAGS = $(ldflags) $(FXT_LDFLAGS) -no-undefined									\
   -version-info $(libstarpu_so_version)
 
 noinst_HEADERS = 						\