diff --git a/src/auto/configure b/src/auto/configure
index 4f43632..be1440d 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -12978,7 +12978,9 @@
 $as_echo_n "checking for libcanberra... " >&6; }
   ac_save_CFLAGS="$CFLAGS"
   ac_save_LIBS="$LIBS"
-  CFLAGS="$CFLAGS $canberra_cflags"
+  if `echo "$CFLAGS" | grep -v "$canberra_cflags" >/dev/null`; then
+    CFLAGS="$CFLAGS $canberra_cflags"
+  fi
   LIBS="$LIBS $canberra_lib"
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
@@ -14960,7 +14962,7 @@
   fi
 fi
 
-if `echo "$CFLAGS" | grep -v D_XEENTRANT >/dev/null`; then
+if `echo "$CFLAGS" | grep -v D_REENTRANT >/dev/null`; then
   CFLAGS="$CFLAGS -D_REENTRANT"
 fi