The fate of Earth depends on this.

In my Makefile, QCC 6.6 on Windows (7)

     echo $$(( 4 * 2 ))
-> 8, correct
     echo $$(( 4 > 2 ))
-> 1, correct
     echo $$(( 4 < 2 ))
-> 0, correct

but

     echo $$(( 4 < 2 ) && ( 5 < 6 ))

[stuff]Temp/make11500-1.sh: line 1: 4 < 2 ) && ( 5 < 6 : syntax error in expression (error token is ") && ( 5 < 6 ")



The question to save Earth (hurry!) is:  What is the magical token string with which to replace && in the expression 
above?  I don't want to do a succession of clumsy ifeq 1 type stuff to create a chain of ands (or ors).