tests: Guard linux specific header includes with ifdef __linux__.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

tests/ChangeLog

@@ -1,3 +1,7 @@
+2016-01-13  Mark Wielaard  <mjw@redhat.com>
+
+	* dwfl-proc-attach.c: Guard linux specific header.
+
 2016-01-13  Mark Wielaard  <mjw@redhat.com>
 
 	* system-elf-libelf-test.c: New test.

tests/dwfl-proc-attach.c

@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <error.h>
 #include <unistd.h>
+#ifdef __linux__
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/user.h>
@@ -29,6 +30,7 @@
 #include <string.h>
 #include ELFUTILS_HEADER(dwfl)
 #include <pthread.h>
+#endif
 
 #ifndef __linux__
 int