If I treat the makefile

---------------------
.SILENT

all: a /b

a /b:
	echo $@ done.
---------------------

then I get the following message:

make.exe: *** No rule to make target 'a', needed by 'all'. Stop.


If I write  t w o  spaces in the target list between 'a' and '/b'
like in the makefile

---------------------
.SILENT

all: a /b

a  /b:
	echo $@ done.
---------------------

then make works correct and I get the message

a done.
/b done.

The bug occurs because the second target '/b' starts with a slash.
If I write 'c:/b' instead of '/b' then one space between 'a' and
'c:/b' is enough.
So the following makefile will be treated correct:

--------------------
.SILENT

all: a c:/b

a c:/b:
	echo $@ done.
---------------------

Note: If the target list 'a /b' is generated by variable substitution
      and/or filter-commands then there is just one space between 'a'
      and '/b' and you are not able to influence this.

This is the result of the same bug that screws up static pattern
rules.  The patch that should fix it is in bug 127, which see.