Replace math.deg/math.rad with builtin Lua function.

src/host/buildvm_libbc.h

@@ -3,10 +3,13 @@
 static const int libbc_endian = 0;
 
 static const uint8_t libbc_code[] = {
-0
+0,1,2,0,0,1,2,22,1,0,0,72,1,2,0,241,135,158,166,3,220,203,178,130,4,0,1,2,0,
+0,1,2,22,1,0,0,72,1,2,0,243,244,148,165,20,198,190,199,252,3,0
 };
 
 static const struct { const char *name; int ofs; } libbc_map[] = {
-{NULL,0}
+{"math_deg",0},
+{"math_rad",25},
+{NULL,50}
 };