libc - Freestanding standard library

Makar ships a minimal freestanding C library (libc/) that provides just enough of the standard C interface for the kernel to compile against. It is not a full POSIX libc - it exists solely to satisfy the #include dependencies of the kernel and its subdirectories.

Modules

Header	Source(s)	Description
`stdio.h`	`stdio/printf.c`, `putchar.c`, `puts.c`	Formatted and character output.
`stdlib.h`	`stdlib/abort.c`	Abnormal termination.
`string.h`	`string/mem*.c`, `strlen.c`	Memory and string utilities.
`sys/cdefs.h`	-	Compiler/libc identification macros.

`sys/cdefs.h`

#define __makar_libc 1

Identifies this as the Makar freestanding libc. Code that needs to detect the Makar environment at compile time can test #ifdef __makar_libc.

Design notes

All sources are compiled with -ffreestanding - no hosted runtime is available.
putchar is the single output primitive; printf and puts are built on top of it. The kernel’s tty.c supplies the concrete putchar implementation via the linker.
No dynamic memory allocation (malloc/free) is provided here; the kernel’s own kmalloc/kfree heap is used instead.
No floating-point, no locale, no signal handling, no file I/O beyond the terminal.

Future work

Add <stdarg.h>-compatible vprintf / snprintf for safer formatted output in kernel subsystems.
Extend printf to support %d, %u, %x, %p format specifiers fully.
Consider a kernel-space <errno.h> for richer error reporting from syscall stubs.