LibC: Port setjmp syntax to avoid nasm dependency

LibC/setjmp.S

@@ -0,0 +1,31 @@
+.global setjmp
+setjmp:
+    mov 4(%esp), %eax
+    mov %ebx, 0(%eax)
+    mov %esi, 4(%eax)
+    mov %edi, 8(%eax)
+    mov %ebp, 12(%eax)
+    lea 4(%esp), %ecx
+    mov %ecx, 16(%eax)
+    mov (%esp), %ecx
+    mov %ecx, 20(%eax)
+    xor %eax, %eax
+    ret
+
+.global longjmp
+longjmp:
+    mov 4(%esp), %edx
+    mov 8(%esp), %eax
+    mov 0(%edx), %ebx
+    mov 4(%edx), %esi
+    mov 8(%edx), %edi
+    mov 12(%edx), %ebp
+    mov 16(%edx), %ecx
+    mov %ecx, %esp
+    mov 20(%edx), %ecx
+    test %eax, %eax
+    jnz  .nonzero
+    mov 1, %eax
+.nonzero:
+    jmp *%ecx
+