libctf, elfcpp, gold: do not assume that <byteswap.h> contains bswap_*

At least one C library (uclibc-ng) defines some of these only when
the compiler is GCC.  We might as well test for all three cases and
handle any of them being missing.

Very similar code exists in libctf and split between elfcpp and gold:
fix both.

(Also sync up elfcpp with a change made to libctf swap.h a few months
ago: since there is no out-of-line definition of the bswap replacements,
they should be declared static inline, not just inline, to prevent the
linker generating out-of-line references to them.)

	PR libctf/25120
libctf/
	* configure.ac: Check for bswap_16, bswap_32, and bswap_64 decls.
	* swap.h (bswap_16): Do not assume that presence of <byteswap.h>
	means this is declared.
	(bswap_32): Likewise.
	(bswap_64): Likewise.
	(bswap_identity_64): Remove, unused.
	* configure: Regenerated.
	* config.h.in: Likewise.
gold/
	* configure.ac: Check for bswap_16, bswap_32, and bswap_64 decls.
	* configure: Regenerated.
	* config.h.in: Likewise.
elfcpp/
	* elfcpp_swap.h (bswap_16): Do not assume that presence of
	<byteswap.h> means this is declared.  Make static inline, matching
	recent change to libctf, since there is no non-inline definition
	of these functions.
	(bswap_32): Likewise.
	(bswap_64): Likewise.

1 files changed, 81 insertions, 46 deletions

diff --git a/gold/configure b/gold/configure
index 474c69a..199a739 100755
--- a/gold/configure
+++ b/gold/configure
@@ -2167,6 +2167,52 @@ fi
 
 } # ac_fn_cxx_check_header_mongrel
 
+# ac_fn_cxx_check_decl LINENO SYMBOL VAR INCLUDES
+# -----------------------------------------------
+# Tests whether SYMBOL is declared in INCLUDES, setting cache variable VAR
+# accordingly.
+ac_fn_cxx_check_decl ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  as_decl_name=`echo $2|sed 's/ *(.*//'`
+  as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
+$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
+if eval \${$3+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$4
+int
+main ()
+{
+#ifndef $as_decl_name
+#ifdef __cplusplus
+  (void) $as_decl_use;
+#else
+  (void) $as_decl_name;
+#endif
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  eval "$3=yes"
+else
+  eval "$3=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$$3
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_cxx_check_decl
+
 # ac_fn_cxx_try_link LINENO
 # -------------------------
 # Try to link conftest.$ac_ext, and return whether this succeeded.
@@ -2279,52 +2325,6 @@ $as_echo "$ac_res" >&6; }
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_cxx_check_func
-
-# ac_fn_cxx_check_decl LINENO SYMBOL VAR INCLUDES
-# -----------------------------------------------
-# Tests whether SYMBOL is declared in INCLUDES, setting cache variable VAR
-# accordingly.
-ac_fn_cxx_check_decl ()
-{
-  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  as_decl_name=`echo $2|sed 's/ *(.*//'`
-  as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
-$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
-if eval \${$3+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-$4
-int
-main ()
-{
-#ifndef $as_decl_name
-#ifdef __cplusplus
-  (void) $as_decl_use;
-#else
-  (void) $as_decl_name;
-#endif
-#endif
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_cxx_try_compile "$LINENO"; then :
-  eval "$3=yes"
-else
-  eval "$3=no"
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-fi
-eval ac_res=\$$3
-	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
-$as_echo "$ac_res" >&6; }
-  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
-
-} # ac_fn_cxx_check_decl
 cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
@@ -9780,6 +9780,41 @@ fi
 done
 
 
+ac_fn_cxx_check_decl "$LINENO" "bswap_16" "ac_cv_have_decl_bswap_16" "#include <byteswap.h>
+"
+if test "x$ac_cv_have_decl_bswap_16" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_BSWAP_16 $ac_have_decl
+_ACEOF
+ac_fn_cxx_check_decl "$LINENO" "bswap_32" "ac_cv_have_decl_bswap_32" "#include <byteswap.h>
+"
+if test "x$ac_cv_have_decl_bswap_32" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_BSWAP_32 $ac_have_decl
+_ACEOF
+ac_fn_cxx_check_decl "$LINENO" "bswap_64" "ac_cv_have_decl_bswap_64" "#include <byteswap.h>
+"
+if test "x$ac_cv_have_decl_bswap_64" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_BSWAP_64 $ac_have_decl
+_ACEOF
+
+
 for ac_header in windows.h
 do :
   ac_fn_cxx_check_header_mongrel "$LINENO" "windows.h" "ac_cv_header_windows_h" "$ac_includes_default"