[Bug ada/55243] STAMP variable is not defined in t-avr

[gjl at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55243

--- Comment #14 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-12-10 18:25:19 UTC ---
(In reply to comment #12)

> So t-multilib is autogenerated in the source tree during the build???

Jepp.  Top $(srcdir)/gcc/config/avr/t-multilib reads:


# Auto-generated Makefile Snip
# Generated by    : ./gcc/config/avr/genmultilib.awk
# Generated from  : ./gcc/config/avr/avr-mcus.def
# Used by         : tmake_file from Makefile and genmultilib


Rationale is that avr-gcc supports an, IMHO, insane number of -mmcu=<device>. 
In order to keep various parts of the compiler in sync, some bits are
auto-generated, amongst them documentation, t-multilib and .opt parts.

Procedure is a move-if-change scheme, i.e. the auto-generated files are in the
repository and the procedure to build them is similar to building configure
from configure.ac and then putting both configure.ac /and/ configure into the
repo.

However, the auto-build runs automatically and thus needs some tools, namely 
$(SHELL), $(AWK), $(CC_FOR_BUILD), $(RUN_GEN) and $(STAMP).