[gcc r13-1579] libbacktrace: check for sys/link.h

[gcc r13-1579] libbacktrace: check for sys/link.h

[Ian Lance Taylor]

https://gcc.gnu.org/g:55bb77b50a5ec520f28978ac3fdac1983200e1f7

commit r13-1579-g55bb77b50a5ec520f28978ac3fdac1983200e1f7
Author: Ian Lance Taylor <iant@golang.org>
Date:   Fri Jul 8 10:28:24 2022 -0700

    libbacktrace: check for sys/link.h
    
    QNX uses sys/link.h rather than link.h for dl_iterate_phdr
    
    Fixes https://github.com/ianlancetaylor/libbacktrace/issues/86
    
            * configure.ac: Check for sys/link.h.  Use either link.h or
            sys/link.h when checking for dl_iterate_phdr.
            * elf.c: Include sys/link.h if available.
            * configure, config.h.in: Regenerate.

Diff:
---
 libbacktrace/config.h.in  |  3 +++
 libbacktrace/configure    | 17 +++++++++++------
 libbacktrace/configure.ac | 10 +++++++---
 libbacktrace/elf.c        |  7 ++++++-
 4 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/libbacktrace/config.h.in b/libbacktrace/config.h.in
index cdb416e6406..a21e2eaf525 100644
--- a/libbacktrace/config.h.in
+++ b/libbacktrace/config.h.in
@@ -85,6 +85,9 @@
 /* Define to 1 if you have the <sys/ldr.h> header file. */
 #undef HAVE_SYS_LDR_H
 
+/* Define to 1 if you have the <sys/link.h> header file. */
+#undef HAVE_SYS_LINK_H
+
 /* Define to 1 if you have the <sys/mman.h> header file. */
 #undef HAVE_SYS_MMAN_H
 
diff --git a/libbacktrace/configure b/libbacktrace/configure
index 537486d34f2..705b71bd8cd 100755
--- a/libbacktrace/configure
+++ b/libbacktrace/configure
@@ -13267,26 +13267,31 @@ fi
 
 
 # Check for dl_iterate_phdr.
-for ac_header in link.h
+for ac_header in link.h sys/link.h
 do :
-  ac_fn_c_check_header_mongrel "$LINENO" "link.h" "ac_cv_header_link_h" "$ac_includes_default"
-if test "x$ac_cv_header_link_h" = xyes; then :
+  as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
+ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
-#define HAVE_LINK_H 1
+#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
 
 fi
 
 done
 
-if test "$ac_cv_header_link_h" = "no"; then
+if test "$ac_cv_header_link_h" = "no" -a "$ac_cv_header_sys_link_h" = "no"; then
   have_dl_iterate_phdr=no
 else
   if test -n "${with_target_subdir}"; then
+    link_h=link.h
+    if test "$ac_cv_header_link_h" = "no"; then
+       link_h=sys/link.h
+    fi
     # When built as a GCC target library, we can't do a link test.
     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <link.h>
+#include <$link_h>
 
 _ACEOF
 if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
diff --git a/libbacktrace/configure.ac b/libbacktrace/configure.ac
index 857987a2859..1daaa2f62d2 100644
--- a/libbacktrace/configure.ac
+++ b/libbacktrace/configure.ac
@@ -335,13 +335,17 @@ fi
 AC_SUBST(BACKTRACE_USES_MALLOC)
 
 # Check for dl_iterate_phdr.
-AC_CHECK_HEADERS(link.h)
-if test "$ac_cv_header_link_h" = "no"; then
+AC_CHECK_HEADERS(link.h sys/link.h)
+if test "$ac_cv_header_link_h" = "no" -a "$ac_cv_header_sys_link_h" = "no"; then
   have_dl_iterate_phdr=no
 else
   if test -n "${with_target_subdir}"; then
+    link_h=link.h
+    if test "$ac_cv_header_link_h" = "no"; then
+       link_h=sys/link.h
+    fi
     # When built as a GCC target library, we can't do a link test.
-    AC_EGREP_HEADER([dl_iterate_phdr], [link.h], [have_dl_iterate_phdr=yes],
+    AC_EGREP_HEADER([dl_iterate_phdr], [$link_h], [have_dl_iterate_phdr=yes],
 		    [have_dl_iterate_phdr=no])
   else
     AC_CHECK_FUNC([dl_iterate_phdr], [have_dl_iterate_phdr=yes],
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 8b82dd45875..181d195fe35 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -40,7 +40,12 @@ POSSIBILITY OF SUCH DAMAGE.  */
 #include <unistd.h>
 
 #ifdef HAVE_DL_ITERATE_PHDR
-#include <link.h>
+ #ifdef HAVE_LINK_H
+  #include <link.h>
+ #endif
+ #ifdef HAVE_SYS_LINK_H
+  #include <sys/link.h>
+ #endif
 #endif
 
 #include "backtrace.h"