fix: align POSIX stdio and argument handling, clarify Intel iwlwifi licensing

programs/lib/libc/libc.c

@@ -2081,8 +2081,35 @@ int open(const char *path, int flags, ...) {
     return h;
 }
 
+/*
+ * The standard descriptors are the terminal, NOT file handles.
+ *
+ * 0/1/2 are not handles the kernel ever issued -- SYS_OPEN allocates from its
+ * own space and would have to return 0 for these to line up, which it does
+ * not. Passing them to SYS_READ/SYS_FWRITE addresses whatever handle happens
+ * to hold that number, or fails: before this, every write(2, ...) was
+ * silently discarded, so a POSIX program that reports errors with write()
+ * rather than fprintf() printed nothing at all. stdio already routes std
+ * streams to SYS_PUTCHAR (see fwrite/fprintf); these do the same, so the two
+ * paths agree.
+ */
 int read(int fd, void *buf, size_t count) {
     if (buf == NULL) return -1;
+
+    if (fd == STDIN_FILENO) {
+        /* Line-oriented, like the terminal itself: return as soon as a
+           line is complete rather than blocking for the full count. */
+        char *dst = (char *)buf;
+        size_t i = 0;
+        while (i < count) {
+            int c = fgetc(stdin);
+            if (c == EOF) break;
+            dst[i++] = (char)c;
+            if (c == '\n') break;
+        }
+        return (int)i;
+    }
+
     unsigned long pos = (fd >= 0 && fd < _FD_POS_MAX) ? _fd_pos[fd] : 0;
     int ret = (int)_zos_syscall4(SYS_READ, (long)fd, (long)buf, (long)pos, (long)count);
     if (ret > 0 && fd >= 0 && fd < _FD_POS_MAX)
@@ -2092,6 +2119,14 @@ int read(int fd, void *buf, size_t count) {
 
 int write(int fd, const void *buf, size_t count) {
     if (buf == NULL) return -1;
+
+    if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
+        const char *src = (const char *)buf;
+        for (size_t i = 0; i < count; i++)
+            _zos_syscall1(SYS_PUTCHAR, (long)(unsigned char)src[i]);
+        return (int)count;
+    }
+
     unsigned long pos = (fd >= 0 && fd < _FD_POS_MAX) ? _fd_pos[fd] : 0;
     int ret = (int)_zos_syscall4(SYS_FWRITE, (long)fd, (long)buf, (long)pos, (long)count);
     if (ret > 0 && fd >= 0 && fd < _FD_POS_MAX)