Fix build with glibc 2.34.  Adapted from:
https://github.com/gcc-mirror/gcc/commit/331763de7d4850702a0f67298f36017c73cdb103
--- a/gcc/ada/init.c
+++ b/gcc/ada/init.c
@@ -579,12 +579,8 @@
 
 #ifndef __ia64__
 #define HAVE_GNAT_ALTERNATE_STACK 1
-/* This must be in keeping with System.OS_Interface.Alternate_Stack_Size.
-   It must be larger than MINSIGSTKSZ and hopefully near 2 * SIGSTKSZ.  */
-# if 16 * 1024 < MINSIGSTKSZ
-#  error "__gnat_alternate_stack too small"
-# endif
-char __gnat_alternate_stack[16 * 1024];
+/* This must be in keeping with System.OS_Interface.Alternate_Stack_Size.  */
+char __gnat_alternate_stack[32 * 1024];
 #endif
 
 #ifdef __XENO__
--- a/gcc/ada/s-osinte-linux.ads
+++ b/gcc/ada/s-osinte-linux.ads
@@ -328,7 +328,7 @@
       oss : access stack_t) return int;
    pragma Import (C, sigaltstack, "sigaltstack");
 
-   Alternate_Stack_Size : constant := 16 * 1024;
+   Alternate_Stack_Size : constant := 32 * 1024;
    --  This must be in keeping with init.c:__gnat_alternate_stack
 
    Alternate_Stack : aliased char_array (1 .. Alternate_Stack_Size);