diff --git a/configure b/configure
index acef2495d..343e67cd3 100755
--- a/configure
+++ b/configure
@@ -5515,9 +5515,8 @@ extract() {
   IFS=$SAVEIFS
 }
 
-extract $CPPFLAGS
+extract "$CFLAGS $CPPFLAGS $CXXFLAGS"
 QBT_ADD_DEFINES="$QBT_ADD_DEFINES $QBT_CONF_DEFINES"
-QBT_CONF_EXTRA_CFLAGS="$QBT_CONF_EXTRA_CFLAGS $CXXFLAGS"
 
 # Substitute the values of these vars in conf.pri.in
 
diff --git a/configure.ac b/configure.ac
index ba9f09e7c..4456e289f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -204,9 +204,8 @@ extract() {
   IFS=$SAVEIFS
 }
 
-extract $CPPFLAGS
+extract "$CFLAGS $CPPFLAGS $CXXFLAGS"
 QBT_ADD_DEFINES="$QBT_ADD_DEFINES $QBT_CONF_DEFINES"
-QBT_CONF_EXTRA_CFLAGS="$QBT_CONF_EXTRA_CFLAGS $CXXFLAGS"
 
 # Substitute the values of these vars in conf.pri.in
 AC_SUBST(QBT_CONF_INCLUDES)