gentoo-overlay/games-action/bzflag/files/bzflag-2.4.12-sdl2-cppflags.patch

--- a/configure.ac
+++ b/configure.ac
@@ -236,6 +236,7 @@
 AC_PROG_CC
 AC_PROG_LN_S
 AC_CHECK_PROG(AR, ar, ar)
+PKG_PROG_PKG_CONFIG
 AC_SUBST(AR)
 AC_SUBST(AR_FLAGS)
 
@@ -716,6 +717,8 @@
 fi
 if test "x$with_SDL" = "x2"; then
     AC_DEFINE(HAVE_SDL2, 1, [Using SDL2])
+    PKG_CHECK_MODULES(sdl2, sdl2,
+        [CONF_CPPFLAGS="$CONF_CPPFLAGS $sdl2_CFLAGS"],[])
 fi
 
 AM_CONDITIONAL(HAVE_SDL, test x$with_SDL = x1 -o x$with_SDL = x2)