win32: fix libtcc support

For "tcc -run file.c", I was trying to initialize the FP control
in a function in libtcc1.a (_runmain) before calling main.

Unfortunately that turned out to cause problems with for example
libtcc_test since such usage doesn't necessarily define a 'main'
function.

So for tcc -run we're back to relying on the FP control word
that is set in the startup code of tcc.exe rsp. libtcc.dll.

This fixes part of commit 73faaea227

win32/lib/crt1.c

@@ -31,10 +31,4 @@ int _start(void)
     exit(ret);
 }
 
-int _runmain(int argc, char **argv)
-{
-    _controlfp(0x10000, 0x30000);
-    return main(argc, argv, NULL);
-}
-
 // =============================================