Introduce & use redirectfd() for musl compatibility

src/filterdiff.c

@@ -1828,15 +1828,10 @@ int main (int argc, char *argv[])
 
 			if (inplace_mode) {
 				/* Redirect stdout to temporary file for in-place processing */
-				FILE *temp_output = xtmpfile();
-				FILE *old_stdout = stdout;
-				stdout = temp_output;
+				FILE *temp_output = redirectfd(stdout);
 
 				filterdiff (f, argv[i]);
 
-				/* Restore stdout */
-				stdout = old_stdout;
-
 				/* Write temp file contents back to original file */
 				if (write_file_inplace(argv[i], temp_output) != 0) {
 					error (EXIT_FAILURE, errno, "failed to write %s", argv[i]);

src/util.c

@@ -116,6 +116,30 @@ FILE *xtmpfile (void)
 	return ret;
 }
 
+FILE *redirectfd (FILE* fd)
+{
+	FILE *ret;
+	char *tmpfname;
+	char *tmpdir = getenv ("TMPDIR");
+	size_t tmpdirlen;
+
+	if (tmpdir == NULL) {
+		tmpdir = P_tmpdir;
+	}
+
+	tmpdirlen = strlen (tmpdir);
+	tmpfname = xmalloc (tmpdirlen + 8);
+	strcpy (tmpfname, tmpdir);
+	strcpy (tmpfname + tmpdirlen, "/XXXXXX");
+	close(mkstemp(tmpfname));
+	ret = freopen (tmpfname, "w+b", fd);
+	if (ret == NULL)
+		error (EXIT_FAILURE, errno, "freopen");
+	unlink (tmpfname);
+	free (tmpfname);
+	return ret;
+}
+
 /*
  * Pattern operations.
  */

src/util.h

@@ -42,6 +42,8 @@ char *xstrndup (const char *s, const size_t n);
 int xmkstemp (char *pattern);
 /* safe tmpfile */
 FILE *xtmpfile (void);
+/* redirect fd to temp file */
+FILE *redirectfd (FILE* fd);
 
 FILE *xopen(const char *file, const char *mode);
 FILE *xopen_seekable(const char *file, const char *mode);