build: Move feature test macros to prelude.h

This replaces the explicit CPPFLAGS list in flags.mk with just
`-include src/prelude.h`, shortening our compiler command lines and
allowing them to be easily documented.

1 files changed, 0 insertions, 1 deletions

diff --git a/src/opt.c b/src/opt.c
index f75d9c9..425a540 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -25,7 +25,6 @@
  * effects are reachable at all, skipping the traversal if not.
  */
 
-#include "prelude.h"
 #include "opt.h"
 
 #include "bfs.h"