Use a more rigorous check for library containing backtrace().

.travis/install-debian.sh

@@ -5,6 +5,6 @@ sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
 sudo add-apt-repository -y 'deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.9 main'
 sudo apt-get update -qq
 sudo apt-get install -q -y \
-  cmake cmake-data libpng12-dev zlib1g-dev libjson0-dev libfontconfig1-dev \
+  cmake cmake-data libc6-dev libpng12-dev zlib1g-dev libjson0-dev libfontconfig1-dev \
   libgtkmm-3.0-dev libpangomm-1.4-dev libcairo2-dev libgl1-mesa-dev libglu-dev \
   libfreetype6-dev dpkg-dev libstdc++-5-dev clang-3.9 clang++-3.9 lcov

src/CMakeLists.txt

@@ -6,7 +6,13 @@ include_directories(
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_BINARY_DIR})
 
+set(HAVE_BACKTRACE ${Backtrace_FOUND})
+if(HAVE_BACKTRACE)
+    set(BACKTRACE_HEADER <${Backtrace_HEADER}>)
+endif()
+
 set(HAVE_SPACEWARE ${SPACEWARE_FOUND})
+
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in
                ${CMAKE_CURRENT_BINARY_DIR}/config.h)
 
@@ -75,6 +81,11 @@ include_directories(
     ${FREETYPE_INCLUDE_DIRS}
     ${CAIRO_INCLUDE_DIRS})
 
+if(Backtrace_FOUND)
+    include_directories(
+        ${Backtrace_INCLUDE_DIRS})
+endif()
+
 if(SPACEWARE_FOUND)
     include_directories(
         ${SPACEWARE_INCLUDE_DIR})
@@ -208,8 +219,12 @@ target_link_libraries(solvespace-core
     ${util_LIBRARIES}
     ${ZLIB_LIBRARY}
     ${PNG_LIBRARY}
-    ${FREETYPE_LIBRARY}
-    ${Backtrace_LIBRARIES})
+    ${FREETYPE_LIBRARY})
+
+if(Backtrace_FOUND)
+    target_link_libraries(solvespace-core
+        ${Backtrace_LIBRARY})
+endif()
 
 target_compile_options(solvespace-core
     PRIVATE ${COVERAGE_FLAGS})

src/config.h.in

@@ -9,6 +9,11 @@
 /* Do we have the si library on win32, or libspnav on *nix? */
 #cmakedefine HAVE_SPACEWARE
 
+/* What OpenGL version do we use? */
 #define HAVE_OPENGL @OPENGL@
 
+/* Do we have backtrace() function, and if yes, in which library? */
+#cmakedefine HAVE_BACKTRACE
+#define BACKTRACE_HEADER @BACKTRACE_HEADER@
+
 #endif

src/platform/unixutil.cpp

@@ -7,8 +7,11 @@
 // Copyright 2008-2013 Jonathan Westhues.
 // Copyright 2013 Daniel Richard G. <skunk@iSKUNK.ORG>
 //-----------------------------------------------------------------------------
-#include <execinfo.h>
+#include "config.h"
 #include "solvespace.h"
+#if defined(HAVE_BACKTRACE)
+#  include BACKTRACE_HEADER
+#endif
 
 namespace SolveSpace {
 
@@ -29,7 +32,7 @@ void assert_failure(const char *file, unsigned line, const char *function,
     fprintf(stderr, "File %s, line %u, function %s:\n", file, line, function);
     fprintf(stderr, "Assertion '%s' failed: ((%s) == false).\n", message, condition);
 
-#ifndef LIBRARY
+#if !defined(LIBRARY) && defined(HAVE_BACKTRACE)
     static void *ptrs[1024] = {};
     size_t nptrs = backtrace(ptrs, sizeof(ptrs) / sizeof(ptrs[0]));
     char **syms = backtrace_symbols(ptrs, nptrs);
@@ -44,6 +47,8 @@ void assert_failure(const char *file, unsigned line, const char *function,
             fprintf(stderr, "%2zu: %p\n", i, ptrs[i]);
         }
     }
+#else
+    fprintf(stderr, "Backtrace support not compiled in.\n");
 #endif
 
     abort();