libctf: Add configure check for asprintf (for MinGW)

This commit fixes a compilation warning when compiling libctf
on MinGW:

    libctf/ctf-dump.c:118:8: warning: implicit declaration of function
    'asprintf'; did you mean 'vasprintf'? [-Wimplicit-function-declaration]

	 if (asprintf (&bit, " %lx: [slice 0x%x:0x%x]",
	     ^~~~~~~~
	     vasprintf

MinGW doesn't provide that function, so we depend on the one provided
by libiberty. However, the declaration is guarded by HAVE_DECL_ASPRINTF,
which we do not have in libctf's config.h.

libctf/ChangeLog:

	PR binutils/25155:
	* configure.ac: Add AC_CHECK_DECLS([asprintf]).
	* configure, config.h.in: Regenerate.

libctf/ChangeLog

@@ -1,3 +1,9 @@
+2020-02-05  Joel Brobecker  <brobecker@adacore.com>
+
+	PR binutils/25155:
+	* configure.ac: Add AC_CHECK_DECLS([asprintf]).
+	* configure, config.h.in: Regenerate.
+
 2020-01-01  Alan Modra  <amodra@gmail.com>
 
 	Update year range in copyright notice of all files.

libctf/config.h.in

@@ -9,6 +9,10 @@
 /* Define to 1 if you have the <byteswap.h> header file. */
 #undef HAVE_BYTESWAP_H
 
+/* Define to 1 if you have the declaration of `asprintf', and to 0 if you
+   don't. */
+#undef HAVE_DECL_ASPRINTF
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 

libctf/configure

@@ -1875,6 +1875,52 @@ $as_echo "$ac_res" >&6; }
   eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_c_check_func
+
+# ac_fn_c_check_decl LINENO SYMBOL VAR INCLUDES
+# ---------------------------------------------
+# Tests whether SYMBOL is declared in INCLUDES, setting cache variable VAR
+# accordingly.
+ac_fn_c_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) $as_decl_name;
+#endif
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$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; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_c_check_decl
 cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
@@ -11385,7 +11431,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11388 "configure"
+#line 11434 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11491,7 +11537,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11494 "configure"
+#line 11540 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12971,6 +13017,18 @@ fi
 done
 
 
+ac_fn_c_check_decl "$LINENO" "asprintf" "ac_cv_have_decl_asprintf" "$ac_includes_default"
+if test "x$ac_cv_have_decl_asprintf" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_ASPRINTF $ac_have_decl
+_ACEOF
+
+
 
 
 

libctf/configure.ac

@@ -99,6 +99,8 @@ AC_C_BIGENDIAN
 AC_CHECK_HEADERS(byteswap.h endian.h)
 AC_CHECK_FUNCS(pread)
 
+AC_CHECK_DECLS([asprintf])
+
 dnl Check for qsort_r.  (Taken from gnulib.)
 AC_CHECK_FUNCS_ONCE([qsort_r])
 if test $ac_cv_func_qsort_r = yes; then