Have example/library check !WUFFS_IMPLEMENTATION
@@ -40,6 +40,9 @@ for a C compiler $CC, such as clang or gcc.
//
// By #include'ing it "as is" without #define'ing WUFFS_IMPLEMENTATION, we use
// it as a "foo.h"-like header, instead of a "foo.c"-like implementation.
+#if defined(WUFFS_IMPLEMENTATION)
+#error "example/library should not #define WUFFS_IMPLEMENTATION"
+#endif
#include "wuffs/release/c/wuffs-unsupported-snapshot.c"
#ifndef DST_BUFFER_SIZE
