[gcc r12-5751] [Ada] Add warning in comment about files copied from libgnat

[gcc r12-5751] [Ada] Add warning in comment about files copied from libgnat

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:c9dd01314d8467e3f6615b6e800ba25706d70320

commit r12-5751-gc9dd01314d8467e3f6615b6e800ba25706d70320
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Fri Nov 26 11:06:36 2021 +0100

    [Ada] Add warning in comment about files copied from libgnat
    
    gcc/ada/
    
            * gcc-interface/Make-lang.in (ADA_GENERATED_FILES): Add warning.

Diff:
---
 gcc/ada/gcc-interface/Make-lang.in | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gcc/ada/gcc-interface/Make-lang.in b/gcc/ada/gcc-interface/Make-lang.in
index c01945b4b9f..911deb7f078 100644
--- a/gcc/ada/gcc-interface/Make-lang.in
+++ b/gcc/ada/gcc-interface/Make-lang.in
@@ -1181,6 +1181,10 @@ ada/mdll-utl.o : ada/mdll-utl.adb ada/mdll.ads ada/mdll-utl.ads ada/sdefault.ads
 
 # All generated files.  Perhaps we should build all of these in the same
 # subdirectory, and get rid of ada/bldtools.
+# Warning: the files starting with ada/gnat.ads are not really generated,
+# instead they are copied from the libgnat subdirectory of the source tree
+# during all the stages of the bootstrap, i.e. including stage #1, which
+# means that they still need to be compilable by the base compiler.
 ADA_GENERATED_FILES = \
   ada/sinfo.h ada/einfo.h ada/nmake.adb ada/nmake.ads \
   ada/snames.ads ada/snames.adb ada/snames.h \