implement stdlib.h stubs. This allows things to be pulled in that are…

…nt completely freestanding.

include/kernel.h

@@ -28,7 +28,7 @@
 #include "kmalloc.h"
 #include "pci.h"
 #include "maths.h"
-#include "pngle.h"
+#include "stdlib.h"
 #include "devicename.h"
 #include "interrupt.h"
 #include "ahci.h"

include/stb_image.h

@@ -381,7 +381,7 @@ enum
    STBI_rgb_alpha  = 4
 };
 
-//#include <stdlib.h>
+#include <stdlib.h>
 typedef unsigned char stbi_uc;
 typedef unsigned short stbi_us;
 
@@ -584,8 +584,8 @@ STBIDEF int   stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const ch
 
 #include <stdarg.h>
 #include <stddef.h> // ptrdiff_t on osx
-//#include <stdlib.h>
-//#include <string.h>
+#include <stdlib.h>
+#include <string.h>
 #include <limits.h>
 
 #if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)

include/stdlib.h

@@ -0,0 +1,62 @@
+/**
+ * @file stdlib.h
+ * @author Craig Edwards
+ * @brief Standard library stubs
+ * @date 2023-05-27
+ * @copyright Copyright (c) 2023
+ */
+#include <stddef.h>
+#include <stdint.h>
+
+#pragma once
+
+typedef struct div_t {
+	int quot;
+	int rem;
+} div_t;
+
+typedef struct ldiv_t {
+	long int quot;
+	long int rem;
+} ldiv_t;
+
+typedef char schar_t;
+
+double strtod(const char *str, char **endptr);
+
+long int strtol(const char *str, char **endptr, int base);
+
+unsigned long int strtoul(const char *str, char **endptr, int base);
+
+void abort(void);
+
+int atexit(void (*func)(void));
+
+void exit(int status);
+
+char *getenv(const char *name);
+
+int system(const char *string);
+
+void *bsearch(const void *key, const void *base, size_t nitems, size_t size, int (*compar)(const void *, const void *));
+
+void qsort(void *base, size_t nitems, size_t size, int (*compar)(const void *, const void*));
+
+div_t div(int numer, int denom);
+
+ldiv_t ldiv(long int numer, long int denom);
+
+int rand(void);
+
+void srand(unsigned int seed);
+
+int mblen(const char *str, size_t n);
+
+size_t mbstowcs(schar_t *pwcs, const char *str, size_t n);
+
+int mbtowc(wchar_t *pwc, const char *str, size_t n);
+
+size_t wcstombs(char *str, const wchar_t *pwcs, size_t n);
+
+int wctomb(char *str, wchar_t wchar);
+

include/string.h

@@ -25,6 +25,8 @@ int strnicmp(const char* s1, const char* s2, uint32_t n);
 
 char toupper(char low);
 
+int isupper(const char x);
+
 char tolower(char low);
 
 int isalnum(const char x);