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

fusl/arch/i386/bits/mman.h

+#define MAP_FAILED ((void *) -1)
+
+#define PROT_NONE      0
+#define PROT_READ      1
+#define PROT_WRITE     2
+#define PROT_EXEC      4
+#define PROT_GROWSDOWN 0x01000000
+#define PROT_GROWSUP   0x02000000
+
+#define MAP_SHARED     0x01
+#define MAP_PRIVATE    0x02
+#define MAP_FIXED      0x10
+
+#define MAP_TYPE       0x0f
+#define MAP_FILE       0x00
+#define MAP_ANON       0x20
+#define MAP_ANONYMOUS  MAP_ANON
+#define MAP_32BIT      0x40
+#define MAP_NORESERVE  0x4000
+#define MAP_GROWSDOWN  0x0100
+#define MAP_DENYWRITE  0x0800
+#define MAP_EXECUTABLE 0x1000
+#define MAP_LOCKED     0x2000
+#define MAP_POPULATE   0x8000
+#define MAP_NONBLOCK   0x10000
+#define MAP_STACK      0x20000
+#define MAP_HUGETLB    0x40000
+
+#define POSIX_MADV_NORMAL       0
+#define POSIX_MADV_RANDOM       1
+#define POSIX_MADV_SEQUENTIAL   2
+#define POSIX_MADV_WILLNEED     3
+#define POSIX_MADV_DONTNEED     0
+
+#define MS_ASYNC        1
+#define MS_INVALIDATE   2
+#define MS_SYNC         4
+
+#define MCL_CURRENT     1
+#define MCL_FUTURE      2
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define MADV_NORMAL      0
+#define MADV_RANDOM      1
+#define MADV_SEQUENTIAL  2
+#define MADV_WILLNEED    3
+#define MADV_DONTNEED    4
+#define MADV_REMOVE      9
+#define MADV_DONTFORK    10
+#define MADV_DOFORK      11
+#define MADV_MERGEABLE   12
+#define MADV_UNMERGEABLE 13
+#define MADV_HUGEPAGE    14
+#define MADV_NOHUGEPAGE  15
+#define MADV_DONTDUMP    16
+#define MADV_DODUMP      17
+#define MADV_HWPOISON    100
+#define MADV_SOFT_OFFLINE 101
+#endif