diff --git a/external/libxmlsec/ExternalProject_xmlsec.mk b/external/libxmlsec/ExternalProject_xmlsec.mk
index 33b07121f5b9..781f22fe587f 100644
--- a/external/libxmlsec/ExternalProject_xmlsec.mk
+++ b/external/libxmlsec/ExternalProject_xmlsec.mk
@@ -55,6 +55,7 @@ $(call gb_ExternalProject_get_state_target,xmlsec,build) :
 		autoreconf \
 		&& ./configure \
 			--with-pic --disable-shared --disable-crypto-dl --without-libxslt --without-gnutls \
+			CFLAGS="$(if $(debug),$(gb_COMPILERNOOPTFLAGS) $(gb_DEBUG_CFLAGS),$(gb_COMPILEROPTFLAGS))" \
 			$(if $(or $(filter-out ANDROID,$(OS)),$(DISABLE_OPENSSL)),--without-openssl,--with-openssl=$(call gb_UnpackedTarball_get_dir,openssl)) \
 			$(if $(filter MACOSX,$(OS)),--prefix=/@.__________________________________________________OOO) \
 			$(if $(SYSTEM_NSS),,$(if $(filter MACOSX,$(OS)),--disable-pkgconfig)) \