Updated to version 2.31.1 for RC build

configure

@@ -3516,7 +3516,7 @@ orig_CFLAGS="$CFLAGS"
 # See docs/release_checklist.md
 SDL_MAJOR_VERSION=2
 SDL_MINOR_VERSION=31
-SDL_MICRO_VERSION=0
+SDL_MICRO_VERSION=1
 SDL_VERSION=$SDL_MAJOR_VERSION.$SDL_MINOR_VERSION.$SDL_MICRO_VERSION
 
 SDL_BINARY_AGE=`expr $SDL_MINOR_VERSION \* 100 + $SDL_MICRO_VERSION`
@@ -14246,11 +14246,11 @@ if test x$ac_prog_cxx_stdcxx = xno
 then :
   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CXX option to enable C++11 features" >&5
 printf %s "checking for $CXX option to enable C++11 features... " >&6; }
-if test ${ac_cv_prog_cxx_cxx11+y}
+if test ${ac_cv_prog_cxx_11+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
-  ac_cv_prog_cxx_cxx11=no
+  ac_cv_prog_cxx_11=no
 ac_save_CXX=$CXX
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
@@ -14292,11 +14292,11 @@ if test x$ac_prog_cxx_stdcxx = xno
 then :
   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CXX option to enable C++98 features" >&5
 printf %s "checking for $CXX option to enable C++98 features... " >&6; }
-if test ${ac_cv_prog_cxx_cxx98+y}
+if test ${ac_cv_prog_cxx_98+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
-  ac_cv_prog_cxx_cxx98=no
+  ac_cv_prog_cxx_98=no
 ac_save_CXX=$CXX
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
@@ -19260,15 +19260,13 @@ then :
   ac_cv_func_alloca_works=yes
 else $as_nop
   ac_cv_func_alloca_works=no
-
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.beam \
     conftest$ac_exeext conftest.$ac_ext
 fi
-
-fi
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_alloca_works" >&5
 printf "%s\n" "$ac_cv_func_alloca_works" >&6; }
+fi
 
 if test $ac_cv_func_alloca_works = yes; then