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

fusl/arch/x32/reloc.h

+#define LDSO_ARCH "x32"
+
+/* FIXME: x32 is very strange in its use of 64-bit relocation types in
+ * a 32-bit environment. As long as the memory at reloc_addr is
+ * zero-filled prior to relocations, just treating 64-bit relocations
+ * as operating on 32-bit slots should be fine, but this should be
+ * checked. In particular, R_X86_64_64, R_X86_64_DTPOFF64, and
+ * R_X86_64_TPOFF64 may need checking. */
+
+/* The R_X86_64_64, R_X86_64_DTPOFF32, and R_X86_64_TPOFF32 reloc types
+ * were previously mapped in the switch table form of this file; however,
+ * they do not seem to be used/usable for anything. If needed, new
+ * mappings will have to be added. */
+
+#define REL_SYMBOLIC    R_X86_64_32
+#define REL_OFFSET      R_X86_64_PC32
+#define REL_GOT         R_X86_64_GLOB_DAT
+#define REL_PLT         R_X86_64_JUMP_SLOT
+#define REL_RELATIVE    R_X86_64_RELATIVE
+#define REL_COPY        R_X86_64_COPY
+#define REL_DTPMOD      R_X86_64_DTPMOD64
+#define REL_DTPOFF      R_X86_64_DTPOFF64
+#define REL_TPOFF       R_X86_64_TPOFF64
+
+#define CRTJMP(pc,sp) __asm__ __volatile__( \
+        "mov %1,%%esp ; jmp *%0" : : "r"((uint64_t)(uintptr_t)pc), "r"(sp) : "memory" )
+
+#define GETFUNCSYM(fp, sym, got) __asm__ ( \
+        ".hidden " #sym "\n" \
+        "       lea " #sym "(%%rip),%0\n" \
+        : "=r"(*fp) : : "memory" )