libsodium: add autoreconf

The patch, while it works, requires autoreconf. Added.

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

libs/libsodium/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libsodium
 PKG_VERSION:=1.0.18
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://download.libsodium.org/libsodium/releases \
@@ -21,6 +21,7 @@ PKG_LICENSE:=ISC
 PKG_LICENSE_FILES:=LICENSE
 
 PKG_USE_MIPS16:=0
+PKG_FIXUP:=autoreconf
 PKG_INSTALL:=1
 PKG_BUILD_PARALLEL:=1