ibrdtn: fix compilation with GCC11

GCC11 defaults to C++17, which does now allow specifying throw().

Signed-off-by: Rosen Penev <rosenp@gmail.com>

libs/ibrdtn/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ibrdtn
 PKG_VERSION:=1.0.1
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://www.ibr.cs.tu-bs.de/projects/ibr-dtn/releases
@@ -37,6 +37,8 @@ CONFIGURE_ARGS += \
 	--with-compression \
 	--without-glib
 
+TARGET_CXXFLAGS +=-std=c++11
+
 define Build/InstallDev
 	$(INSTALL_DIR) $(1)
 	$(CP) $(PKG_INSTALL_DIR)/* $(1)/