bpo-45548: Remove _math.c workarounds for pre-C99 libm (GH-29179)

The :mod:`math` and :mod:`cmath` implementation now require a C99 compatible
``libm`` and no longer ship with workarounds for missing acosh, asinh,
expm1, and log1p functions.

The changeset also removes ``_math.c`` and moves the last remaining
workaround into ``_math.h``. This simplifies static builds with
``Modules/Setup`` and resolves symbol conflicts.

Co-authored-by: Mark Dickinson <mdickinson@enthought.com>
Co-authored-by: Brett Cannon <brett@python.org>
Signed-off-by: Christian Heimes <christian@python.org>

1 files changed, 4 insertions, 12 deletions

diff --git a/configure b/configure
index 198b070..b72660d 100755
--- a/configure
+++ b/configure
@@ -15092,7 +15092,7 @@ fi
 LIBS_SAVE=$LIBS
 LIBS="$LIBS $LIBM"
 
-for ac_func in acosh asinh atanh erf erfc expm1 finite gamma
+for ac_func in acosh asinh atanh erf erfc expm1 finite gamma lgamma log1p log2 tgamma
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
@@ -15101,21 +15101,13 @@ if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
 
-fi
-done
-
-for ac_func in lgamma log1p log2 tgamma
-do :
-  as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
-ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
-  cat >>confdefs.h <<_ACEOF
-#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
-_ACEOF
+else
+  as_fn_error $? "Python requires C99 compatible libm" "$LINENO" 5
 
 fi
 done
 
+LIBS=$LIBS_SAVE
 
 # For multiprocessing module, check that sem_open
 # actually works.  For FreeBSD versions <= 7.2,