userspace: Rewrite everything

Everything.

Signed-off-by: EnderIce2 <enderice2@protonmail.com>

Userspace/libc/include/assert.h

@@ -1,4 +1,43 @@
+/*
+	This file is part of Fennix C Library.
+
+	Fennix C Library is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix C Library is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix C Library. If not, see <https://www.gnu.org/licenses/>.
+*/
+
 #ifndef _ASSERT_H
 #define _ASSERT_H
 
-#endif
+#ifdef __cplusplus
+extern "C"
+{
+#endif // __cplusplus
+
+	void __assert_fail(const char *file, int line, const char *func) __attribute__((noreturn));
+
+#ifdef NDEBUG
+#define assert(e) ((void)0)
+#else // NDEBUG
+#define assert(e)                                        \
+	do                                                   \
+	{                                                    \
+		if (__builtin_expect(!!(!(e)), 0))               \
+			__assert_fail(__FILE__, __LINE__, __func__); \
+	} while (0)
+#endif // NDEBUG
+
+#ifdef __cplusplus
+}
+#endif // __cplusplus
+
+#endif // !_ASSERT_H