automake/gallium: attempt to fix -lrt

fix non-automake bits in pipe-load to.

Should fix:
http://bugs.freedesktop.org/57852

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/configure.ac b/configure.ac
index 803c256..a133902 100644
--- a/configure.ac
+++ b/configure.ac
@@ -535,6 +535,11 @@
        [DEFINES="$DEFINES -DHAVE_DLOPEN"; DLOPEN_LIBS="-ldl"])])
 AC_SUBST([DLOPEN_LIBS])
 
+AC_CHECK_FUNCS([clock_gettime], [CLOCK_LIB=],
+               [AC_CHECK_LIB([rt], [clock_gettime], [CLOCK_LIB=-lrt],
+                             [AC_MSG_ERROR([Couldn't find clock_gettime])])])
+AC_SUBST([CLOCK_LIB])
+
 dnl See if posix_memalign is available
 AC_CHECK_FUNC([posix_memalign], [DEFINES="$DEFINES -DHAVE_POSIX_MEMALIGN"])
 
@@ -1121,7 +1126,7 @@
 
     # put all the necessary libs together
     DRI_LIB_DEPS="$DRI_LIB_DEPS $SELINUX_LIBS $LIBDRM_LIBS $EXPAT_LIB -lm $PTHREAD_LIBS $DLOPEN_LIBS"
-    GALLIUM_DRI_LIB_DEPS="$GALLIUM_DRI_LIB_DEPS $SELINUX_LIBS $LIBDRM_LIBS $EXPAT_LIB -lm $PTHREAD_LIBS $DLOPEN_LIBS"
+    GALLIUM_DRI_LIB_DEPS="$GALLIUM_DRI_LIB_DEPS $SELINUX_LIBS $LIBDRM_LIBS $EXPAT_LIB -lm $CLOCK_LIB $PTHREAD_LIBS $DLOPEN_LIBS"
 fi
 AM_CONDITIONAL(NEED_LIBDRICORE, test -n "$DRI_DIRS")
 AC_SUBST([DRI_DIRS])
@@ -1390,7 +1395,7 @@
     CORE_DIRS="$CORE_DIRS mapi/vgapi"
     GALLIUM_STATE_TRACKERS_DIRS="vega $GALLIUM_STATE_TRACKERS_DIRS"
     HAVE_ST_VEGA=yes
-    VG_PC_LIB_PRIV="-lm $PTHREAD_LIBS $DLOPEN_LIBS"
+    VG_PC_LIB_PRIV="-lm $CLOCK_LIB $PTHREAD_LIBS $DLOPEN_LIBS"
     AC_SUBST([VG_PC_LIB_PRIV])
 fi