Add a "fork" of musl as //fusl.

fusl/src/passwd/getgrent_a.c

Index: fusl/src/passwd/getgrent_a.c
diff --git a/fusl/src/passwd/getgrent_a.c b/fusl/src/passwd/getgrent_a.c
new file mode 100644
index 0000000000000000000000000000000000000000..7fc389d46332a9ef408d29c67d853978a5dc5082
--- /dev/null
+++ b/fusl/src/passwd/getgrent_a.c
@@ -0,0 +1,68 @@
+#include "pwf.h"
+#include <pthread.h>
+
+static unsigned atou(char **s)
+{
+	unsigned x;
+	for (x=0; **s-'0'<10U; ++*s) x=10*x+(**s-'0');
+	return x;
+}
+
+int __getgrent_a(FILE *f, struct group *gr, char **line, size_t *size, char ***mem, size_t *nmem, struct group **res)
+{
+	ssize_t l;
+	char *s, *mems;
+	size_t i;
+	int rv = 0;
+	int cs;
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+	for (;;) {
+		if ((l=getline(line, size, f)) < 0) {
+			rv = ferror(f) ? errno : 0;
+			free(*line);
+			*line = 0;
+			gr = 0;
+			goto end;
+		}
+		line[0][l-1] = 0;
+
+		s = line[0];
+		gr->gr_name = s++;
+		if (!(s = strchr(s, ':'))) continue;
+
+		*s++ = 0; gr->gr_passwd = s;
+		if (!(s = strchr(s, ':'))) continue;
+
+		*s++ = 0; gr->gr_gid = atou(&s);
+		if (*s != ':') continue;
+
+		*s++ = 0; mems = s;
+		break;
+	}
+
+	for (*nmem=!!*s; *s; s++)
+		if (*s==',') ++*nmem;
+	free(*mem);
+	*mem = calloc(sizeof(char *), *nmem+1);
+	if (!*mem) {
+		rv = errno;
+		free(*line);
+		*line = 0;
+		gr = 0;
+		goto end;
+	}
+	if (*mems) {
+		mem[0][0] = mems;
+		for (s=mems, i=0; *s; s++)
+			if (*s==',') *s++ = 0, mem[0][++i] = s;
+		mem[0][++i] = 0;
+	} else {
+		mem[0][0] = 0;
+	}
+	gr->gr_mem = *mem;
+end:
+	pthread_setcancelstate(cs, 0);
+	*res = gr;
+	if(rv) errno = rv;
+	return rv;
+}