Use modern C++ attributes instead of __attribute__ voodoo.

This is quite nice, although I wish [[gnu::always_inline]] implied inline.
Also "gnu::" is kind of a wart, but whatcha gonna do.

LibC/assert.h

@@ -4,7 +4,7 @@
 
 __BEGIN_DECLS
 
-void __assertion_failed(const char* msg, const char* file, unsigned line, const char* func) __attribute__ ((noreturn));
+[[noreturn]] void __assertion_failed(const char* msg, const char* file, unsigned line, const char* func);
 
 #define assert(expr) ((expr) ? (void)0 : __assertion_failed(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__))
 #define CRASH() do { asm volatile("ud2"); } while(0)

LibC/ctype.h

@@ -4,41 +4,41 @@
 
 __BEGIN_DECLS
 
-ALWAYS_INLINE int isascii(int ch)
+[[gnu::always_inline]] inline int isascii(int ch)
 {
     return (ch & ~0x7f) == 0;
 }
 
-ALWAYS_INLINE int isspace(int ch)
+[[gnu::always_inline]] inline int isspace(int ch)
 {
     return ch == ' ' || ch == '\f' || ch == '\n' || ch == '\r' || ch == '\t' || ch == '\v';
 }
 
-ALWAYS_INLINE int islower(int c)
+[[gnu::always_inline]] inline int islower(int c)
 {
     return c >= 'a' && c <= 'z';
 }
 
-ALWAYS_INLINE int isupper(int c)
+[[gnu::always_inline]] inline int isupper(int c)
 {
     return c >= 'A' && c <= 'Z';
 }
 
-ALWAYS_INLINE int tolower(int c)
+[[gnu::always_inline]] inline int tolower(int c)
 {
     if (isupper(c))
         return c | 0x20;
     return c;
 }
 
-ALWAYS_INLINE int toupper(int c)
+[[gnu::always_inline]] inline int toupper(int c)
 {
     if (islower(c))
         return c & ~0x20;
     return c;
 }
 
-ALWAYS_INLINE int isdigit(int c)
+[[gnu::always_inline]] inline int isdigit(int c)
 {
     return c >= '0' && c <= '9';
 }

LibC/dirent.cpp

@@ -35,7 +35,7 @@ int closedir(DIR* dirp)
     return rc;
 }
 
-struct sys_dirent {
+struct [[gnu::packed]] sys_dirent {
     ino_t ino;
     byte file_type;
     size_t namelen;
@@ -44,7 +44,7 @@ struct sys_dirent {
     {
         return sizeof(ino_t) + sizeof(byte) + sizeof(size_t) + sizeof(char) * namelen;
     }
-} __attribute__ ((packed));
+};
 
 dirent* readdir(DIR* dirp)
 {

LibC/entry.cpp

@@ -3,15 +3,17 @@
 #include <Kernel/Syscall.h>
 #include <AK/StringImpl.h>
 
-extern "C" int main(int, char**);
+extern "C" {
+
+int main(int, char**);
 
 int errno;
 char** environ;
 
-extern "C" void __malloc_init();
-extern "C" void __stdio_init();
+void __malloc_init();
+void __stdio_init();
 
-extern "C" int _start()
+int _start()
 {
     errno = 0;
 
@@ -39,8 +41,9 @@ epilogue:
     return 20150614;
 }
 
-extern "C" void __cxa_pure_virtual() NORETURN;
-extern "C" void __cxa_pure_virtual()
+[[noreturn]] void __cxa_pure_virtual()
 {
     ASSERT_NOT_REACHED();
 }
+
+}

LibC/stdlib.h

@@ -9,16 +9,16 @@ __BEGIN_DECLS
 #define EXIT_FAILURE 1
 #define MB_CUR_MAX 1
 
-void* malloc(size_t) __MALLOC;
+[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* malloc(size_t);
+[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1, 2)]] void* calloc(size_t nmemb, size_t);
 void free(void*);
-void* calloc(size_t nmemb, size_t);
-void* realloc(void *ptr, size_t);
+[[gnu::returns_nonnull]] void* realloc(void *ptr, size_t);
 char* getenv(const char* name);
 int atoi(const char*);
 long atol(const char*);
 void qsort(void* base, size_t nmemb, size_t size, int (*compar)(const void *, const void *));
-void exit(int status) __NORETURN;
-void abort() __NORETURN;
+[[noreturn]] void exit(int status);
+[[noreturn]] void abort();
 char* ptsname(int fd);
 int ptsname_r(int fd, char* buffer, size_t);
 int abs(int);

LibC/sys/cdefs.h

@@ -2,10 +2,6 @@
 
 #define _POSIX_VERSION 200809L
 
-#define ALWAYS_INLINE inline __attribute__ ((always_inline))
-#define __NORETURN __attribute__ ((noreturn))
-#define __MALLOC __attribute__ ((malloc))
-
 #ifdef __cplusplus
 #define __BEGIN_DECLS extern "C" {
 #define __END_DECLS }