refactor(userspace): build using cmake

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

Userspace/libc/sysdeps/fennix/generic/dl_start.c

@@ -0,0 +1,58 @@
+/*
+	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/>.
+*/
+
+#ifdef FENNIX_DYNAMIC_LOADER
+__attribute__((naked, used, no_stack_protector)) void _dl_start()
+{
+#if defined(__amd64__)
+	__asm__(
+		"xorq %rbp, %rbp\n" /* Clear rbp */
+
+		"push %rdi\n"
+		"push %rsi\n"
+		"push %rdx\n"
+		"push %rcx\n"
+		"push %r8\n"
+		"push %r9\n"
+
+		"call __init_print_buffer\n" /* Call __init_print_buffer */
+		"call _dl_preload\n"		 /* Call _dl_preload */
+		"movl %eax, %edi\n"			 /* Move return value to edi */
+		"cmp $0, %edi\n"			 /* Check if return value is 0 */
+		"jne _exit\n"				 /* If not, jump to _exit */
+
+		"pop %r9\n"
+		"pop %r8\n"
+		"pop %rcx\n"
+		"pop %rdx\n"
+		"pop %rsi\n"
+		"pop %rdi\n"
+
+		"call main\n"		/* Call _dl_main */
+		"movl %eax, %edi\n" /* Move return value to edi */
+		"call _exit\n");	/* Call _exit */
+#elif defined(__i386__)
+#warning "i386 _start not implemented"
+#elif defined(__arm__)
+#warning "arm _start not implemented"
+#elif defined(__aarch64__)
+#warning "aarch64 _start not implemented"
+#else
+#error "Unsupported architecture"
+#endif
+}
+#endif