avr-gcc-config.patch

diff -Nrup a/gcc-9.2.0/libiberty/acinclude.m4 b/libiberty/acinclude.m4
--- a/gcc-9.2.0/libiberty/acinclude.m4	2019-01-19 09:01:34.000000000 -0700
+++ b/gcc-9.2.0/libiberty/acinclude.m4	2020-01-09 22:00:27.183312982 -0700
@@ -147,7 +147,7 @@ if test $ac_cv_os_cray = yes; then
 fi
 
 AC_CACHE_CHECK(stack direction for C alloca, ac_cv_c_stack_direction,
-[AC_TRY_RUN([find_stack_direction ()
+[AC_TRY_RUN([__attribute__ ((noclone,noinline)) find_stack_direction ()
 {
   static char *addr = 0;
   auto char dummy;
diff --git a/config/intdiv0.m4 b/gcc-9.2.0/config/intdiv0.m4
index 55dddcf1..ba906efc 100644
--- a/gcc-9.2.0/config/intdiv0.m4
+++ b/gcc-9.2.0/config/intdiv0.m4
@@ -31,10 +31,10 @@ sigfpe_handler (sig) int sig;
   exit (sig != SIGFPE);
 }
 
-int x = 1;
-int y = 0;
-int z;
-int nan;
+volatile int x = 1;
+volatile int y = 0;
+volatile int z;
+volatile int nan;
 
 int main ()
 {
diff --git a/gcc-9.2.0/libiberty/configure.ac b/gcc-9.2.0/libiberty/configure.ac
index f1ce7601..fc20d228 100644
--- a/gcc-9.2.0/libiberty/configure.ac
+++ b/gcc-9.2.0/libiberty/configure.ac
@@ -661,7 +661,7 @@ if test -z "${setobjs}"; then
   for v in $vars; do
     AC_MSG_CHECKING([for $v])
     AC_CACHE_VAL(libiberty_cv_var_$v,
-      [AC_LINK_IFELSE([AC_LANG_PROGRAM([[int *p;]],[[extern int $v []; p = $v;]])],
+      [AC_LINK_IFELSE([AC_LANG_PROGRAM([[__attribute__ ((used)) int *p;]],[[extern int $v []; p = $v;]])],
 		      [eval "libiberty_cv_var_$v=yes"],
 		      [eval "libiberty_cv_var_$v=no"])])
     if eval "test \"`echo '$libiberty_cv_var_'$v`\" = yes"; then