[Bug bootstrap/78251] config/gettext.m4 and config/iconv.m4 contaminate CPPFLAGS

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78251

--- Comment #5 from Iain Sandoe <iains at gcc dot gnu.org> ---
is this a GCC bug, or really a gettext /iconv one?
(the comments at the top of the file suggest that these two m4 modules have
been imported)

A quick scan of the code suggests that the writers intended the CPPFLAGS to be
saved.  However, variable names like "am_save_CPPFLAGS" can overwrite
previously saved values in the case of nested configuration tests; it's a very
common choice of save name and I have seen this in GCC config problems before.

If you change the am_save_CPPFLAGS in the iconv m4 to am_iconv_save_CPPFLAGS
(and regenerate all configures that include it) does that resolve the issue? 

 It looks like the gettext save value is already  intended to be specific
(gt_save_CPPFLAGS)