esp8266: Enable float support, using 30-bit stuffed floats.

No complex numbers though.
diff --git a/esp8266/esp8266.ld b/esp8266/esp8266.ld
index e2f1b80..15f9232 100644
--- a/esp8266/esp8266.ld
+++ b/esp8266/esp8266.ld
@@ -81,6 +81,7 @@
 
         /* we put some specific text in this section */
         *py/*.o*(.literal* .text*)
+        *lib/libm/*.o*(.literal*, .text*)
         *pyexec.o(.literal*, .text*)
         *readline.o(.literal*, .text*)
         *pybstdio.o(.literal*, .text*)