From b7a166acaddc4c78afa2b653e25114d9114699f3 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Sat, 6 Aug 2016 11:24:50 +0200
Subject: [PATCH] Proper detection of cxxabi.h and execinfo.h

The current code in webrtc/base/checks.cc assumes that if __GLIBCXX__ is
defined and __UCLIBC__ is not defined, then both cxxabi.h and execinfo.h
will be available.

Unfortunately, this is not correct with the musl C library:

 - It defines __GLIBCXX__
 - It does not define __UCLIBC__ (it's not uClibc after all!)
 - But it also doesn't provide execinfo.h

Therefore, in order to make things work properly, we switch to proper
autoconf checks for cxxabi.h and execinfo.h, and only use the backtrace
functionality if both are provided.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 configure.ac          | 2 ++
 webrtc/base/checks.cc | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index acbb3e2..ff4c752 100644
--- a/configure.ac
+++ b/configure.ac
@@ -45,6 +45,8 @@ AC_SUBST(GNUSTL_CFLAGS)
 # Borrowed from gst-plugins-bad
 AC_CHECK_HEADER(MobileCoreServices/MobileCoreServices.h, HAVE_IOS="yes", HAVE_IOS="no", [-])
 
+AC_CHECK_HEADERS([cxxabi.h execinfo.h])
+
 # Based on gst-plugins-bad configure.ac and defines in
 # <chromium source>/build/config/BUILDCONFIG.gn and
 # webrtc/BUILD.gn
diff --git a/webrtc/base/checks.cc b/webrtc/base/checks.cc
index 49a31f2..05d23a6 100644
--- a/webrtc/base/checks.cc
+++ b/webrtc/base/checks.cc
@@ -16,7 +16,7 @@
 #include <cstdio>
 #include <cstdlib>
 
-#if defined(__GLIBCXX__) && !defined(__UCLIBC__)
+#if defined(HAVE_CXX_ABI_H) && defined(HAVE_EXECINFO_H)
 #include <cxxabi.h>
 #include <execinfo.h>
 #endif
@@ -55,7 +55,7 @@ void PrintError(const char* format, ...) {
 // to get usable symbols on Linux. This is copied from V8. Chromium has a more
 // advanced stace trace system; also more difficult to copy.
 void DumpBacktrace() {
-#if defined(__GLIBCXX__) && !defined(__UCLIBC__)
+#if defined(HAVE_CXX_ABI_H) && defined(HAVE_EXECINFO_H)
   void* trace[100];
   int size = backtrace(trace, sizeof(trace) / sizeof(*trace));
   char** symbols = backtrace_symbols(trace, size);
-- 
2.7.4