Fix leak BacktraceState (enable-dbgutil)

buffer is created from sal/osl/unx/backtraceapi.cxx with:
70     auto b1 = new void *[maxDepth];
71     int n = backtrace(b1, static_cast<int>(maxDepth));
72     return std::unique_ptr<BacktraceState>(new BacktraceState{ b1, n });

and from sal/osl/w32/backtrace.cxx with:
79     auto pStack = new void *[maxDepth];
80     // https://msdn.microsoft.com/en-us/library/windows/desktop/bb204633.aspx
81     // "CaptureStackBackTrace function" claims that you "can capture up to
82     // MAXUSHORT frames", and on Windows Server 2003 and Windows XP it even
83     // "must be less than 63", but assume that a too large input value is
84     // clamped internally, instead of resulting in an error:
85     int nFrames = CaptureStackBackTrace( 0, static_cast<ULONG>(maxDepth), pStack, nullptr );
86
87     return std::unique_ptr<BacktraceState>(new BacktraceState{ pStack, nFrames });

Introduced with:
https://cgit.freedesktop.org/libreoffice/core/commit/?id=bc9a2ba677ce3fcd46c2bbef6e8faeacb14292c1

Change-Id: Iea0528f5d2b38ff1f3dc4bd50ff035bb100ab981
Reviewed-on: https://gerrit.libreoffice.org/41854
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/sal/backtrace.hxx b/include/sal/backtrace.hxx
index 2c854e102eef..f437a3b73620 100644
--- a/include/sal/backtrace.hxx
+++ b/include/sal/backtrace.hxx
@@ -29,6 +29,7 @@
 struct BacktraceState {
     void** buffer;
     int nDepth;
+    ~BacktraceState() {delete[] buffer;}
 };
 
 SAL_DLLPUBLIC std::unique_ptr<BacktraceState> SAL_CALL sal_backtrace_get(