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

fusl/src/linux/prlimit.c

Index: fusl/src/linux/prlimit.c
diff --git a/fusl/src/linux/prlimit.c b/fusl/src/linux/prlimit.c
new file mode 100644
index 0000000000000000000000000000000000000000..0fe28e10664e9047b1ca1a75bdab78c3e0407723
--- /dev/null
+++ b/fusl/src/linux/prlimit.c
@@ -0,0 +1,27 @@
+#define _GNU_SOURCE
+#include <sys/resource.h>
+#include "syscall.h"
+#include "libc.h"
+
+#define FIX(x) do{ if ((x)>=SYSCALL_RLIM_INFINITY) (x)=RLIM_INFINITY; }while(0)
+
+int prlimit(pid_t pid, int resource, const struct rlimit *new_limit, struct rlimit *old_limit)
+{
+	struct rlimit tmp;
+	int r;
+	if (new_limit && SYSCALL_RLIM_INFINITY != RLIM_INFINITY) {
+		tmp = *new_limit;
+		FIX(tmp.rlim_cur);
+		FIX(tmp.rlim_max);
+		new_limit = &tmp;
+	}
+	r = syscall(SYS_prlimit64, pid, resource, new_limit, old_limit);
+	if (!r && old_limit && SYSCALL_RLIM_INFINITY != RLIM_INFINITY) {
+		FIX(old_limit->rlim_cur);
+		FIX(old_limit->rlim_max);
+	}
+	return r;
+}
+
+#undef prlimit64
+LFS64(prlimit);