[PATCH v4 mtd-utils 3/4] configure.ac: Add a check for execinfo and backtrace

[Fabio Estevam]

musl relies on an external execinfo library to provide backtrace
functionality. If musl cannot link to libexecinfo, the following link
error happens:

| /work/festevam/oe/poky/build/tmp/work/core2-64-poky-linux-musl/mtd-utils/2.3.0/recipe-sysroot-native/usr/bin/x86_64-poky-linux-musl/../../libexec/x86_64-poky-linux-musl/gcc/x86_64-poky-linux-musl/14.2.0/ld: ubifs-utils/libubifs/mkfs_ubifs-io.o: in function `dump_stack':
| /usr/src/debug/mtd-utils/2.3.0/ubifs-utils/common/defs.h:71:(.text+0x25): undefined reference to `backtrace'
....
| collect2: error: ld returned 1 exit status
| make: *** [Makefile:2959: mkfs.ubifs] Error 1

Fix the problem by checking for backtrace support in libc first and if not
found, then check for backtrace support in the external libexecinfo.

Signed-off-by: Fabio Estevam <festevam at gmail.com>
Suggested-by: Khem Raj <raj.khem at gmail.com>
Reviewed-by: Zhihao Cheng <chengzhihao1 at huawei.com>
---
Change since v3:
- None.

 configure.ac | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/configure.ac b/configure.ac
index 2a79ba820fc0..296901e61760 100644
--- a/configure.ac
+++ b/configure.ac
@@ -238,6 +238,17 @@ if test "x$need_cmocka" = "xyes"; then
 	PKG_CHECK_MODULES(CMOCKA, [cmocka], [], [cmocka_missing="yes"])
 fi
 
+AC_CHECK_FUNC([backtrace], [have_backtrace=yes], [have_backtrace=no])
+
+if test "x$have_backtrace" = "xno"; then
+    AC_CHECK_LIB([execinfo], [backtrace],
+        [LIBS="$LIBS -lexecinfo"
+         AC_DEFINE([HAVE_BACKTRACE], [1], [backtrace is available via libexecinfo])],
+        [AC_MSG_WARN([backtrace support not found])])
+else
+    AC_DEFINE([HAVE_BACKTRACE], [1], [backtrace is available via libc])
+fi
+
 AC_CHECK_HEADERS([execinfo.h])
 
 ##### produce summary on dependencies #####
-- 
2.34.1