tools/nolibc: Replace ifdef with if defined() in sys.h

Thomas has requested that if defined() be used in place of ifdef but
currently ifdef is used consistently in sys.h. Update all the instances of
ifdef to if defined().

Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250703-arm64-gcs-vfork-exit-v3-1-1e9a9d2ddbbe@kernel.org
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

Author: broonie

tools/include/nolibc/sys.h

@@ -139,7 +139,7 @@ int chdir(const char *path)
 static __attribute__((unused))
 int sys_chmod(const char *path, mode_t mode)
 {
-#ifdef __NR_fchmodat
+#if defined(__NR_fchmodat)
 	return my_syscall4(__NR_fchmodat, AT_FDCWD, path, mode, 0);
 #elif defined(__NR_chmod)
 	return my_syscall2(__NR_chmod, path, mode);
@@ -162,7 +162,7 @@ int chmod(const char *path, mode_t mode)
 static __attribute__((unused))
 int sys_chown(const char *path, uid_t owner, gid_t group)
 {
-#ifdef __NR_fchownat
+#if defined(__NR_fchownat)
 	return my_syscall5(__NR_fchownat, AT_FDCWD, path, owner, group, 0);
 #elif defined(__NR_chown)
 	return my_syscall3(__NR_chown, path, owner, group);
@@ -236,7 +236,7 @@ int dup(int fd)
 static __attribute__((unused))
 int sys_dup2(int old, int new)
 {
-#ifdef __NR_dup3
+#if defined(__NR_dup3)
 	return my_syscall3(__NR_dup3, old, new, 0);
 #elif defined(__NR_dup2)
 	return my_syscall2(__NR_dup2, old, new);
@@ -256,7 +256,7 @@ int dup2(int old, int new)
  * int dup3(int old, int new, int flags);
  */
 
-#ifdef __NR_dup3
+#if defined(__NR_dup3)
 static __attribute__((unused))
 int sys_dup3(int old, int new, int flags)
 {
@@ -320,7 +320,7 @@ void exit(int status)
 static __attribute__((unused))
 pid_t sys_fork(void)
 {
-#ifdef __NR_clone
+#if defined(__NR_clone)
 	/* note: some archs only have clone() and not fork(). Different archs
 	 * have a different API, but most archs have the flags on first arg and
 	 * will not use the rest with no other flag.
@@ -382,7 +382,7 @@ int getdents64(int fd, struct linux_dirent64 *dirp, int count)
 static __attribute__((unused))
 uid_t sys_geteuid(void)
 {
-#ifdef __NR_geteuid32
+#if defined(__NR_geteuid32)
 	return my_syscall0(__NR_geteuid32);
 #else
 	return my_syscall0(__NR_geteuid);
@@ -500,7 +500,7 @@ int getpagesize(void)
 static __attribute__((unused))
 uid_t sys_getuid(void)
 {
-#ifdef __NR_getuid32
+#if defined(__NR_getuid32)
 	return my_syscall0(__NR_getuid32);
 #else
 	return my_syscall0(__NR_getuid);
@@ -538,7 +538,7 @@ int kill(pid_t pid, int signal)
 static __attribute__((unused))
 int sys_link(const char *old, const char *new)
 {
-#ifdef __NR_linkat
+#if defined(__NR_linkat)
 	return my_syscall5(__NR_linkat, AT_FDCWD, old, AT_FDCWD, new, 0);
 #elif defined(__NR_link)
 	return my_syscall2(__NR_link, old, new);
@@ -561,7 +561,7 @@ int link(const char *old, const char *new)
 static __attribute__((unused))
 off_t sys_lseek(int fd, off_t offset, int whence)
 {
-#ifdef __NR_lseek
+#if defined(__NR_lseek)
 	return my_syscall3(__NR_lseek, fd, offset, whence);
 #else
 	return __nolibc_enosys(__func__, fd, offset, whence);
@@ -572,7 +572,7 @@ static __attribute__((unused))
 int sys_llseek(int fd, unsigned long offset_high, unsigned long offset_low,
 	       __kernel_loff_t *result, int whence)
 {
-#ifdef __NR_llseek
+#if defined(__NR_llseek)
 	return my_syscall5(__NR_llseek, fd, offset_high, offset_low, result, whence);
 #else
 	return __nolibc_enosys(__func__, fd, offset_high, offset_low, result, whence);
@@ -609,7 +609,7 @@ off_t lseek(int fd, off_t offset, int whence)
 static __attribute__((unused))
 int sys_mkdir(const char *path, mode_t mode)
 {
-#ifdef __NR_mkdirat
+#if defined(__NR_mkdirat)
 	return my_syscall3(__NR_mkdirat, AT_FDCWD, path, mode);
 #elif defined(__NR_mkdir)
 	return my_syscall2(__NR_mkdir, path, mode);
@@ -631,7 +631,7 @@ int mkdir(const char *path, mode_t mode)
 static __attribute__((unused))
 int sys_rmdir(const char *path)
 {
-#ifdef __NR_rmdir
+#if defined(__NR_rmdir)
 	return my_syscall1(__NR_rmdir, path);
 #elif defined(__NR_unlinkat)
 	return my_syscall3(__NR_unlinkat, AT_FDCWD, path, AT_REMOVEDIR);
@@ -654,7 +654,7 @@ int rmdir(const char *path)
 static __attribute__((unused))
 long sys_mknod(const char *path, mode_t mode, dev_t dev)
 {
-#ifdef __NR_mknodat
+#if defined(__NR_mknodat)
 	return my_syscall4(__NR_mknodat, AT_FDCWD, path, mode, dev);
 #elif defined(__NR_mknod)
 	return my_syscall3(__NR_mknod, path, mode, dev);
@@ -843,7 +843,7 @@ pid_t setsid(void)
 static __attribute__((unused))
 int sys_symlink(const char *old, const char *new)
 {
-#ifdef __NR_symlinkat
+#if defined(__NR_symlinkat)
 	return my_syscall3(__NR_symlinkat, old, AT_FDCWD, new);
 #elif defined(__NR_symlink)
 	return my_syscall2(__NR_symlink, old, new);
@@ -900,7 +900,7 @@ int umount2(const char *path, int flags)
 static __attribute__((unused))
 int sys_unlink(const char *path)
 {
-#ifdef __NR_unlinkat
+#if defined(__NR_unlinkat)
 	return my_syscall3(__NR_unlinkat, AT_FDCWD, path, 0);
 #elif defined(__NR_unlink)
 	return my_syscall1(__NR_unlink, path);