Possible bug in Makefile 3.81

[address@hidden]

Consider the following Makefile:

*** BEGIN Makefile ***

all:
  if [[ -n "string" ]]; then echo "hello"; fi

*** END Makefile ***


The expected output is the next one:

address@hidden:$ make
if [[ -n "string" ]]; then echo "hello"; fi
hello



It works as expected  when executing it on
a computer with:
  * make 3.81beta4
  * bash version 3.1.17(1)-release

However it fails in a computer with:
  * make 3.81
  * bash version 3.2.25(1)-release




The output error is the next one:

address@hidden:$ make
if [[ -n "string" ]]; then echo "hello"; fi
/bin/sh: [[: not found




If I change the Makefile into this new one:

*** BEGIN Makefile ***

all:
  if test -n "string" ; then echo "hello"; fi

*** END Makefile ***



...then everything work ok again.

It looks like "make" won't allow bash "[["
built-in to be "executed?".

Any idea ??