A partial reverse for commit eda2c756edc4dca004ba217d5bf361235dd9de1f

A partial reverse for commit eda2c756edc4dca004ba217d5bf361235dd9de1f

	Author: Thomas Preud'homme <robotux@celest.fr>
	Date:   Tue Dec 31 23:51:20 2013 +0800

	Move logic for if (int value) to tccgen.c
	Move the logic to do a test of an integer value (ex if (0)) out of
	arch-specific code to tccgen.c to avoid code duplication. This also
        fixes test of long long value which was only testing the bottom half of
	such values on 32 bits architectures.

I don't understand why if () in gtst(i) was removed.
This patch allows to compile a linux kernel v.2.4.26
W/o this patch a tcc simply crashes.