Re: make: avoid breaking backwards compatability

[christos%astron.com@localhost (Christos Zoulas)]

In article <20140904223618.GC805%apb-laptoy.apb.alt.za@localhost>,
Alan Barrett  <apb%cequrux.com@localhost> wrote:
>On Thu, 04 Sep 2014, Jarmo Jaakkola wrote:
>> If you want foo.o made from foo.S instead of foo.c, use
>>    .SUFFIXES: .S .c
>> instead of
>>    .SUFFIXES: .c .S
>>
>> If you need to consistently override on a file-by-file basis, then I'd
>> say your file hierarchy or build process needs refactoring.
>
>We do want to consistently override on a file by file basis. 
>There might be a foo.c and bar.c with portable code, and several 
>different foo.S and bar.S in different subdirectories for 
>different machine platforms or different optimisation strategies. 
>We want to tell make exactly which .S file or .c file to use, 
>using conditions depending on the machine platform, and foo and 
>bar could easily want different conditional choices.

But you couldn't do that well even before... You had to list
all the possible suffixes in the production like:

# do not pick up the i387 asm version, it is incorrect
s_modf.o s_modf.pico s_modf.po s_modf.d: s_modf.c

Now you just do:

s_modf.S: .INVISIBLE

christos