You can write a conditional that tests make command flags such as
`-t' by using the variable MAKEFLAGS together with the
findstring function
(see section Functions for String Substitution and Analysis).
This is useful when touch is not enough to make a file appear up
to date.
The findstring function determines whether one string appears as a
substring of another. If you want to test for the `-t' flag,
use `t' as the first string and the value of MAKEFLAGS as
the other.
For example, here is how to arrange to use `ranlib -t' to finish marking an archive file up to date:
archive.a: ...
ifneq (,$(findstring t,$(MAKEFLAGS)))
+touch archive.a
+ranlib -t archive.a
else
ranlib archive.a
endif
The `+' prefix marks those command lines as "recursive" so
that they will be executed despite use of the `-t' flag.
See section Recursive Use of make.