Re: Fix compilation of assembler files with subdir-objects

[Alexandre Duret-Lutz]

Hi Andreas,

Sorry for the delay.  I was rushing for 1.9.2 and this one did
not seem obvious.

>>> "Andreas" == Andreas Schwab <address@hidden> writes:

 Andreas> There are currently two languages that don't define
 Andreas> output_flag: c and asm.  For c there is a special case
 Andreas> that sets output_flag to '-o' when subdir-objects is
 Andreas> enabled.

Ouch, I never noticed that hack before.  This means one of my
earlier patch to fine tune the conditions when Automake requires
AM_PROG_CC_C_O is wrong.  Currently AM_PROG_CC_C_O is required
whenever a object is effectively compiled in subdirectory,
however this code uses `-o' whenever the subdir-objects option
is used (that's quite a difference, especially if subdir-objects
is set globally from AM_INIT_AUTOMAKE).  I guess we should
change this code to use -o only when subdir objects are actually
compiled.  At least for C.

 Andreas> The same handling needs to be applied when compiling
 Andreas> assembler files (which actually uses the same
 Andreas> compiler), otherwise the object files won't end up in
 Andreas> the correct directory.  

For C we also need `compile' to work around compilers that do
not support `-c' and `-o' (don't ask me which). I wonder whether
we should do the same thing here, and add support for assembly
sources to `compile'.  Does there exist some C compiler that
supports assembly but not -c -o?  If not, maybe it's simpler
that we fix output_flag to `-o' for assembly.
-- 
Alexandre Duret-Lutz