aarch64: Always use .init/.fini_array for GNU/Linux

I was wondering why the (now fixed) c-c++-common/attr-retain-[78].c
failures were showing up in the native results for aarch64-linux-gnu
but not in the posted cross results.  It turns out that .init/
.fini_array support is disabled by default for cross builds,
which in turn stops those tests from running.

The test for .init/fini_array support has two parts: one that builds
something with the assembler and linker, and another that compiles
C code and uses preprocessor macros to test the glibc version.
The first test would work with build=host but the second is only
safe for build=target.

However, AArch64 postdates glibc and binutils support for
.init/fini_array by some distance, so it's safe to hard-code the
result to "yes" for cross compilers.

This fixes the only material difference in auto-host.h between
a native and a cross build.

gcc/
	* acinclude.m4 (gcc_AC_INITFINI_ARRAY): When cross-compiling,
	default to yes for aarch64-linux-gnu.
	* configure: Regenerate.

2 files changed, 24 insertions, 4 deletions

diff --git a/gcc/acinclude.m4 b/gcc/acinclude.m4
index 74c1824..f9f6a07 100644
--- a/gcc/acinclude.m4
+++ b/gcc/acinclude.m4
@@ -422,8 +422,18 @@ changequote([,])dnl
 ])],, [gcc_cv_initfini_array=no]);;
     esac
   else
-    AC_MSG_CHECKING(cross compile... guessing)
-    gcc_cv_initfini_array=no
+    case "${target}" in
+      aarch64*-linux-gnu*)
+	# AArch64 postdates glibc support for .init_array/.fini_array,
+	# so we don't need the preprocessor test above.
+	gcc_cv_initfini_array=yes
+	;;
+
+      *)
+	AC_MSG_CHECKING(cross compile... guessing)
+	gcc_cv_initfini_array=no
+	;;
+    esac
   fi])
   enable_initfini_array=$gcc_cv_initfini_array
 ])
diff --git a/gcc/configure b/gcc/configure
index e8ecb3b..33eae54 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -24132,9 +24132,19 @@ fi
 rm -f conftest.err conftest.i conftest.$ac_ext;;
     esac
   else
-    { $as_echo "$as_me:${as_lineno-$LINENO}: checking cross compile... guessing" >&5
+    case "${target}" in
+      aarch64*-linux-gnu*)
+	# AArch64 postdates glibc support for .init_array/.fini_array,
+	# so we don't need the preprocessor test above.
+	gcc_cv_initfini_array=yes
+	;;
+
+      *)
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking cross compile... guessing" >&5
 $as_echo_n "checking cross compile... guessing... " >&6; }
-    gcc_cv_initfini_array=no
+	gcc_cv_initfini_array=no
+	;;
+    esac
   fi
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_initfini_array" >&5