Merge pull request #506 from cj1324/fix_libsodium

libsodium: fixed pkgconfig not found it.

libs/libsodium/Makefile

@@ -62,6 +62,8 @@ define Build/InstallDev
 	$(CP) $(PKG_INSTALL_DIR)/usr/include/sodium/*.h $(1)/usr/include/sodium
 	$(INSTALL_DIR) $(1)/usr/lib
 	$(CP) $(PKG_INSTALL_DIR)/usr/lib/libsodium.{a,so*} $(1)/usr/lib
+	$(INSTALL_DIR) $(1)/usr/lib/pkgconfig
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/libsodium.pc $(1)/usr/lib/pkgconfig/
 endef
 
 define Package/libsodium/install