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

fusl/src/stdio/pclose.c

Index: fusl/src/stdio/pclose.c
diff --git a/fusl/src/stdio/pclose.c b/fusl/src/stdio/pclose.c
new file mode 100644
index 0000000000000000000000000000000000000000..080a426245b67be80d5066a539d2b6fabcf20b4f
--- /dev/null
+++ b/fusl/src/stdio/pclose.c
@@ -0,0 +1,13 @@
+#include "stdio_impl.h"
+#include <errno.h>
+#include <unistd.h>
+
+int pclose(FILE *f)
+{
+	int status, r;
+	pid_t pid = f->pipe_pid;
+	fclose(f);
+	while ((r=__syscall(SYS_wait4, pid, &status, 0, 0)) == -EINTR);
+	if (r<0) return __syscall_ret(r);
+	return status;
+}