[Bug libstdc++/111639] New: HAVE_ACOSF etc. are wrong on avr

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111639

            Bug ID: 111639
           Summary: HAVE_ACOSF etc. are wrong on avr
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---
            Target: avr

The <math.h> in avr-libc does things like this:

extern double acos(double __x) __ATTR_CONST__;
#define acosf   acos            /**< The alias for acos().      */

and then crossconfig.m4 does:

  avr*-*-*)
    AC_DEFINE(HAVE_ACOSF)
    AC_DEFINE(HAVE_ASINF)
    AC_DEFINE(HAVE_ATAN2F)
    AC_DEFINE(HAVE_ATANF)
    AC_DEFINE(HAVE_CEILF)
    AC_DEFINE(HAVE_COSF)
    AC_DEFINE(HAVE_COSHF)
    AC_DEFINE(HAVE_EXPF)
    AC_DEFINE(HAVE_FABSF)
    AC_DEFINE(HAVE_FLOORF)
    AC_DEFINE(HAVE_FMODF)
    AC_DEFINE(HAVE_FREXPF)
    AC_DEFINE(HAVE_SQRTF)
    AC_DEFINE(HAVE_HYPOTF)
    AC_DEFINE(HAVE_LDEXPF)
    AC_DEFINE(HAVE_LOG10F)
    AC_DEFINE(HAVE_LOGF)
    AC_DEFINE(HAVE_MODFF)
    AC_DEFINE(HAVE_POWF)
    AC_DEFINE(HAVE_SINF)
    AC_DEFINE(HAVE_SINHF)
    AC_DEFINE(HAVE_TANF)
    AC_DEFINE(HAVE_TANHF)
    ;;

But this doesn't work, because <cmath> has to #undef all math function names,
so we #undef the acosf macro and then the HAVE_ACOSF macro is left defined but
is now lying.