feat(headers): stddef/stdint/stdbool/limits/float/assert + features wiring

include/iso646.h

@@ -0,0 +1,32 @@
+#ifndef VLIBC_ISO646_H
+#define VLIBC_ISO646_H
+
+/*
+ * vlibc — <iso646.h>.
+ *
+ * Alternative spellings for the bitwise and logical operators. C23 removed
+ * them from the language as alternative tokens, so this header provides them
+ * as macros; in C17 the spellings are lexed as tokens and the macros never
+ * fire, which makes the definitions harmless in both modes. In C++ they are
+ * part of the language, so no macros are defined there.
+ *
+ * This header is ISO C core and is present in every profile.
+ */
+
+#include <vlibc/features.h>
+
+#ifndef __cplusplus
+#define and &&
+#define and_eq &=
+#define bitand &
+#define bitor |
+#define compl ~
+#define not !
+#define not_eq !=
+#define or ||
+#define or_eq |=
+#define xor ^
+#define xor_eq ^=
+#endif
+
+#endif /* VLIBC_ISO646_H */