Correctly define malloc_usable_size

Get correct abort() function definition for Solaris.

diff --git a/memory/mozalloc/mozalloc.cpp b/memory/mozalloc/mozalloc.cpp

--- a/memory/mozalloc/mozalloc.cpp

+++ b/memory/mozalloc/mozalloc.cpp

@@ -208,6 +208,8 @@

 #endif // if defined(HAVE_VALLOC) 

 #ifndef MOZ_STATIC_RUNTIME

+extern "C" size_t malloc_usable_size(const void *ptr);

+

 size_t

 moz_malloc_usable_size(void *ptr)

 {

diff --git a/memory/mozalloc/mozalloc_abort.cpp b/memory/mozalloc/mozalloc_abort.cpp

--- a/memory/mozalloc/mozalloc_abort.cpp

+++ b/memory/mozalloc/mozalloc_abort.cpp

@@ -63,7 +63,11 @@

 //

 // That segmentation fault will be interpreted as another bug by ASan and as a

 // result, ASan will just exit(1) instead of aborting.

+#if defined(SOLARIS)

+void std::abort(void)

+#else

 void abort(void)

+#endif

 {

 #ifdef MOZ_WIDGET_ANDROID

     char msg[64] = {};