In musl stdout, stdin and stderr are read-only unlike in glibc.
This patch changes std* = fopen(...) to freopen(..., std*).

See: https://www.gnu.org/software/libc/manual/html_node/Standard-Streams.html and https://wiki.gentoo.org/wiki/User:Sam/Musl_porting_notes

---
 tools/lvmcmdline.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/lvmcmdline.c b/tools/lvmcmdline.c
index 1e12bed..19da1e5 100644
--- a/tools/lvmcmdline.c
+++ b/tools/lvmcmdline.c
@@ -3384,7 +3384,7 @@ static int _check_standard_fds(void)
 	int err = is_valid_fd(STDERR_FILENO);
 
 	if (!is_valid_fd(STDIN_FILENO) &&
-	    !(stdin = fopen(_PATH_DEVNULL, "r"))) {
+		!freopen(_PATH_DEVNULL, "r", stdin)) {
 		if (err)
 			perror("stdin stream open");
 		else
@@ -3394,7 +3394,7 @@ static int _check_standard_fds(void)
 	}
 
 	if (!is_valid_fd(STDOUT_FILENO) &&
-	    !(stdout = fopen(_PATH_DEVNULL, "w"))) {
+		!freopen(_PATH_DEVNULL, "w", stdout)) {
 		if (err)
 			perror("stdout stream open");
 		/* else no stdout */
@@ -3402,7 +3402,7 @@ static int _check_standard_fds(void)
 	}
 
 	if (!is_valid_fd(STDERR_FILENO) &&
-	    !(stderr = fopen(_PATH_DEVNULL, "w"))) {
+		!freopen(_PATH_DEVNULL, "w", stderr)) {
 		printf("stderr stream open: %s\n",
 		       strerror(errno));
 		return 0;
-- 
2.35.1