diff --git a/configure b/configure
index 762bc6ce7..246624d80 100755
--- a/configure
+++ b/configure
@@ -2026,6 +2026,8 @@ ac_configure="$SHELL $ac_aux_dir/configure"  # Please don't use this var.
 
 
 
+: ${CFLAGS=""}
+: ${CXXFLAGS=""}
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
diff --git a/configure.ac b/configure.ac
index 908366fba..a3164f31e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,8 @@
 AC_INIT([qbittorrent], [v4.3.1], [bugs.qbittorrent.org], [], [https://www.qbittorrent.org/])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])
+: ${CFLAGS=""}
+: ${CXXFLAGS=""}
 AC_PROG_CC
 AC_PROG_CXX
 AC_PROG_SED