bpo-42604: always set EXT_SUFFIX=${SOABI}${SHLIB_SUFFIX} when using configure (GH-23708)

Now all platforms use a value for the "EXT_SUFFIX" build variable derived
from SOABI (for instance in FreeBSD, "EXT_SUFFIX" is now ".cpython-310d.so"
instead of ".so"). Previously only Linux, Mac and VxWorks were using a value
for "EXT_SUFFIX" that included "SOABI".

Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
(cherry picked from commit a44ce6c)

Co-authored-by: Matti Picus <matti.picus@gmail.com>

Author: miss-islington

Misc/NEWS.d/next/Build/2020-12-20-02-35-28.bpo-42604.gRd89w.rst

@@ -0,0 +1,4 @@
+Now all platforms use a value for the "EXT_SUFFIX" build variable derived
+from SOABI (for instance in freeBSD, "EXT_SUFFIX" is now ".cpython-310d.so"
+instead of ".so"). Previosuly only Linux, Mac and VxWorks were using a value
+for "EXT_SUFFIX" that included "SOABI".

configure

@@ -15215,13 +15215,7 @@ _ACEOF
 
 fi
 
-
-case $ac_sys_system in
-    Linux*|GNU*|Darwin|VxWorks)
-	EXT_SUFFIX=.${SOABI}${SHLIB_SUFFIX};;
-    *)
-	EXT_SUFFIX=${SHLIB_SUFFIX};;
-esac
+EXT_SUFFIX=.${SOABI}${SHLIB_SUFFIX}
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking LDVERSION" >&5
 $as_echo_n "checking LDVERSION... " >&6; }

configure.ac

@@ -4674,12 +4674,7 @@ if test "$Py_DEBUG" = 'true' -a "$with_trace_refs" != "yes"; then
 fi
 
 AC_SUBST(EXT_SUFFIX)
-case $ac_sys_system in
-    Linux*|GNU*|Darwin|VxWorks)
-	EXT_SUFFIX=.${SOABI}${SHLIB_SUFFIX};;
-    *)
-	EXT_SUFFIX=${SHLIB_SUFFIX};;
-esac
+EXT_SUFFIX=.${SOABI}${SHLIB_SUFFIX}
 
 AC_MSG_CHECKING(LDVERSION)
 LDVERSION='$(VERSION)$(ABIFLAGS)'