Split up source and added basic support for different targets.

targets/_any/include/string.h

@@ -0,0 +1,21 @@
+
+#pragma once
+
+#if !defined(BAD_APPLE_OS_STRING_H_INCLUDED)
+#define BAD_APPLE_OS_STRING_H_INCLUDED
+
+#include <stddef.h>
+
+#include "./detail/common.h"
+
+BA_EXTERN_C_BEGIN
+
+BA_CXX_NODISCARD int memcmp(const void* lhs, const void* rhs, size_t count) BA_CXX_NOEXCEPT;
+void memcpy(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
+void memmove(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
+void* memset(void* dest, int value, size_t count) BA_CXX_NOEXCEPT;
+BA_CXX_NODISCARD size_t strlen(const char* str) BA_CXX_NOEXCEPT;
+
+BA_EXTERN_C_END
+
+#endif // !defined(BAD_APPLE_OS_STRING_H_INCLUDED)