Fix asm2 compilation where __toread was used.

Author: waywardmonkeys

emcc

@@ -1462,6 +1462,7 @@ try:
         ['stdio', [
          '__overflow.c',
          '__toread.c',
+         '__towrite.c',
          '__uflow.c',
         ]],
         ['stdlib', [

system/lib/libc.symbols

@@ -41,14 +41,13 @@
          W _ZnwjRKSt9nothrow_t
          T __floatscan
          T __overflow
-         T __seek_on_exit
          T __shgetc
          T __shlim
          W __strtod_l
          W __strtof_l
          W __strtold_l
          T __toread
-         W __towrite_used
+         T __towrite
          T __uflow
          T _err
          T _errx

system/lib/libc/musl/readme.txt

@@ -10,4 +10,4 @@ Differences from upstream musl include:
 * Disable FLOCK, FUNLOCK and FFINALLOCK
 * Simplify fputwc to not rely on musl stream internals
 * signgam is no longer a weak alias of __signgam.
-
+* __toread and __towrite have had shutdown functionality removed.

system/lib/libc/musl/src/stdio/__toread.c

@@ -12,13 +12,3 @@ int __toread(FILE *f)
 	f->rpos = f->rend = f->buf;
 	return 0;
 }
-
-static const int dummy = 0;
-weak_alias(dummy, __towrite_used);
-
-void __stdio_exit(void);
-
-void __seek_on_exit()
-{
-	if (!__towrite_used) __stdio_exit();
-}

system/lib/libc/musl/src/stdio/__towrite.c

@@ -0,0 +1,18 @@
+#include "stdio_impl.h"
+
+int __towrite(FILE *f)
+{
+	f->mode |= f->mode-1;
+	if (f->flags & (F_NOWR)) {
+		f->flags |= F_ERR;
+		return EOF;
+	}
+	/* Clear read buffer (easier than summoning nasal demons) */
+	f->rpos = f->rend = 0;
+
+	/* Activate write through the buffer. */
+	f->wpos = f->wbase = f->buf;
+	f->wend = f->buf + f->buf_size;
+
+	return 0;
+}