Merge "Only include ucontext.h when necessary."

libbacktrace/BacktraceImpl.cpp

@@ -19,6 +19,7 @@
 #include <string.h>
 #include <sys/ptrace.h>
 #include <sys/types.h>
+#include <ucontext.h>
 #include <unistd.h>
 
 #include <string>

libbacktrace/BacktraceImpl.h

@@ -21,7 +21,6 @@
 #include <backtrace/BacktraceMap.h>
 
 #include <sys/types.h>
-#include <ucontext.h>
 
 class BacktraceImpl {
 public:

libbacktrace/UnwindCurrent.cpp

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#include <sys/ucontext.h>
 #include <sys/types.h>
+#include <ucontext.h>
 
 #include <backtrace/Backtrace.h>
 #include <backtrace/BacktraceMap.h>

libbacktrace/UnwindPtrace.cpp

@@ -19,6 +19,7 @@
 
 #include <sys/types.h>
 #include <string.h>
+#include <ucontext.h>
 
 #include <libunwind.h>
 #include <libunwind-ptrace.h>