diff -Naur pinball-0.3.1.orig/configure.ac pinball-0.3.1/configure.ac

--- pinball-0.3.1.orig/configure.ac	2015-08-21 19:32:14.737072594 +0200

+++ pinball-0.3.1/configure.ac	2015-08-21 19:33:10.466400862 +0200

@@ -11,8 +11,8 @@

 AM_INIT_AUTOMAKE

 dnl this is a c++ program

-CFLAGS="-g -W -Wall -O2"

-CXXFLAGS="-g -W -Wall -O2"

+:CFLAGS="-g -W -Wall -O2"

+:CXXFLAGS="-g -W -Wall -O2"

 dnl Checks for programs.

 AC_PROG_CC