I decided this feature was too impacting to make the permanent default
behavior. This set of changes makes the default behavior of make the
old behavior (no second expansion). If you want second expansion, you
must define the .SECONDEXPANSION: special target before the first target
that needs it.
This set of changes ONLY fixes explicit and static pattern rules to work
like this. Implicit rules still have second expansion enabled all the
time: I'll work on that next.
Note that there is still a backward-incompatibility: now to get the old
SysV behavior using $$@ etc. in the prerequisites list you need to set
.SECONDEXPANSION: as well.
I did this by adding intelligence into the algorithm such that the
second expansion was only actually performed when the prerequisite list
contained at least one "$", so we knew it is actually needed.
Without this we were using up a LOT more memory, since every single
target (even ones never used by make) had their file variables
initialized. This also used a lot more CPU, since we needed to create
and populate a new variable hash table for every target.
There is one issue remaining with this feature: it leaks memory. In
pattern_search() we now initialize the file variables for every pattern
target, which allocates a hash table, etc. However, sometimes we
recursively invoke pattern_search() (for intermediate files) with an
automatic variable (alloca() I believe) as the file. When that function
returns, obviously, the file variable hash memory is lost.
Incorporate "order-only" prerequisites patch. Wrote a test for it.
The test shows what might be a bug in the code; I need to look at it
more closely (anyway it doesn't behave as I expected). Also I haven't
done the docs yet.
New version of the manual, put into the doc subdir.
Enhancements: $(eval ...) and $(value ...) functions, various bug
fixes, etc. See the ChangeLog.
More to come.
* Update maintainers build process; remove GNUmakefile. Require builders to
run automake && autoreconf by hand.
* Use AC_SUBST_FILE to get the maintMakefile included, rather than GNU
make's include directive, which conflicts with automake 1.4's include
directive.
