Fixed `REPLACE_STDERR` compiler warnings.

Fortune for sink's current commit: Curse − 凶

README.md

@@ -19,7 +19,7 @@ Run `make && sudo make install` to build with full optimisations and install `si
 To build for debugging, run `make debug`. 
 
 ### Compiler flags
-`-DREPLACE_STDERR` - Add to `CFLAGS` when building a target to re-route the program's `stderr` stream to the sink as well. By default, it is closed after the other streams have been successfully rewritten.
+`-DREPLACE_STDERR` - Add to `CFLAGS` when building a target to re-route the program's `stderr` stream to the sink as well. By default, it is left open.
 `-DNO_SEARCH_PATH` - Add to `CFLAGS` when building to prevent the program looking up its argument in the `PATH` environment variable.
 `-DNO_ENV` - Add to `CFLAGS` when building to prevent `envp` passthrough to the `execve()`'d program.
 

sink.c

@@ -95,6 +95,7 @@ int main(int argc, char** argv, char** envp)
 
 #ifdef REPLACE_STDERR
 #define perror(v) ((void)(v)) 
+#pragma GCC diagnostic ignored "-Wunused-value"
 #define eprintf(...) ((void)(__VA_ARGS__))
 #else
 #define eprintf(...) fprintf(stderr, __VA_ARGS__)