Fix unused parameter warnings

-Werror is used for this project so these warnings were causing the
clang build to fail.

Change-Id: I18c447ce239645e05f59c3cf0e2b8bb17d9d3030
Author: Edwin Vane <edwin.vane@intel.com>
Reviewed-by: Tarea A Siraj <tareq.a.siraj@intel.com>
diff --git a/libcorkscrew/arch-x86/backtrace-x86.c b/libcorkscrew/arch-x86/backtrace-x86.c
index 24fadcb..849029f 100644
--- a/libcorkscrew/arch-x86/backtrace-x86.c
+++ b/libcorkscrew/arch-x86/backtrace-x86.c
@@ -73,13 +73,13 @@
     uint32_t esp;
 } unwind_state_t;
 
-uintptr_t rewind_pc_arch(const memory_t* memory, uintptr_t pc) {
+uintptr_t rewind_pc_arch(const memory_t* memory __attribute__((unused)), uintptr_t pc) {
     // TODO: Implement for x86.
     return pc;
 }
 
 static ssize_t unwind_backtrace_common(const memory_t* memory,
-        const map_info_t* map_info_list,
+        const map_info_t* map_info_list __attribute__((unused)),
         unwind_state_t* state, backtrace_frame_t* backtrace,
         size_t ignore_depth, size_t max_depth) {
     size_t ignored_frames = 0;
@@ -108,7 +108,7 @@
     return returned_frames;
 }
 
-ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext,
+ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo __attribute__((unused)), void* sigcontext,
         const map_info_t* map_info_list,
         backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
     const ucontext_t* uc = (const ucontext_t*)sigcontext;