diff --git a/config/spl-build.m4 b/config/spl-build.m4
index 84fbb8b926..1a7512c96b 100644
--- a/config/spl-build.m4
+++ b/config/spl-build.m4
@@ -638,7 +638,7 @@ AC_DEFUN([SPL_AC_ATOMIC_SPINLOCK], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <asm/atomic.h>
 	],[
-		atomic64_t *ptr;
+		atomic64_t *ptr __attribute__ ((unused));
 	],[
 		have_atomic64_t=yes
 		AC_DEFINE(HAVE_ATOMIC64_T, 1,
@@ -720,7 +720,7 @@ AC_DEFUN([SPL_AC_TYPE_UINTPTR_T],
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/types.h>
 	],[
-		uintptr_t *ptr;
+		uintptr_t *ptr __attribute__ ((unused));
 	],[
 		AC_MSG_RESULT([yes])
 		AC_DEFINE(HAVE_UINTPTR_T, 1,
@@ -739,7 +739,7 @@ AC_DEFUN([SPL_AC_3ARGS_INIT_WORK],
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/workqueue.h>
 	],[
-		struct work_struct work;
+		struct work_struct work __attribute__ ((unused));
 		INIT_WORK(&work, NULL, NULL);
 	],[
 		AC_MSG_RESULT(yes)
@@ -759,7 +759,7 @@ AC_DEFUN([SPL_AC_2ARGS_REGISTER_SYSCTL],
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/sysctl.h>
 	],[
-		return register_sysctl_table(NULL,0);
+		(void) register_sysctl_table(NULL, 0);
 	],[
 		AC_MSG_RESULT(yes)
 		AC_DEFINE(HAVE_2ARGS_REGISTER_SYSCTL, 1,
@@ -825,7 +825,7 @@ AC_DEFUN([SPL_AC_PATH_IN_NAMEIDATA],
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/namei.h>
 	],[
-		struct nameidata nd;
+		struct nameidata nd __attribute__ ((unused));
 
 		nd.path.mnt = NULL;
 		nd.path.dentry = NULL;
@@ -877,7 +877,7 @@ AC_DEFUN([SPL_AC_CTL_NAME], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/sysctl.h>
 	],[
-		struct ctl_table ctl;
+		struct ctl_table ctl __attribute__ ((unused));
 		ctl.ctl_name = 0;
 	],[
 		AC_MSG_RESULT(yes)
@@ -997,7 +997,9 @@ AC_DEFUN([SPL_AC_TIMESPEC_SUB], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/time.h>
 	],[
-		struct timespec a, b, c = { 0 };
+		struct timespec a = { 0 };
+		struct timespec b = { 0 };
+		struct timespec c __attribute__ ((unused));
 		c = timespec_sub(a, b);
 	],[
 		AC_MSG_RESULT(yes)
@@ -1016,7 +1018,8 @@ AC_DEFUN([SPL_AC_INIT_UTSNAME], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/utsname.h>
 	],[
-		struct new_utsname *a = init_utsname();
+		struct new_utsname *a __attribute__ ((unused));
+		a = init_utsname();
 	],[
 		AC_MSG_RESULT(yes)
 		AC_DEFINE(HAVE_INIT_UTSNAME, 1, [init_utsname() is available])
@@ -1047,7 +1050,8 @@ AC_DEFUN([SPL_AC_FILES_FDTABLE], [
 		#endif
 	],[
 		struct files_struct *files = current->files;
-		struct fdtable *fdt = files_fdtable(files);
+		struct fdtable *fdt __attribute__ ((unused));
+		fdt = files_fdtable(files);
 	],[
 		AC_MSG_RESULT(yes)
 		AC_DEFINE(HAVE_FILES_FDTABLE, 1, [files_fdtable() is available])
@@ -1073,7 +1077,8 @@ AC_DEFUN([SPL_AC_KMALLOC_NODE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/slab.h>
 	],[
-		void *a = kmalloc_node(1, GFP_KERNEL, 0);
+		void *a __attribute__ ((unused));
+		a = kmalloc_node(1, GFP_KERNEL, 0);
 	],[
 		AC_MSG_RESULT(yes)
 		AC_DEFINE(HAVE_KMALLOC_NODE, 1, [kmalloc_node() is available])
@@ -1125,7 +1130,7 @@ AC_DEFUN([SPL_AC_MUTEX_OWNER], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mutex.h>
 	],[
-		struct mutex mtx;
+		struct mutex mtx __attribute__ ((unused));
 		mtx.owner = NULL;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1301,7 +1306,7 @@ AC_DEFUN([SPL_AC_GLOBAL_PAGE_STATE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		unsigned long state;
+		unsigned long state __attribute__ ((unused));
 		state = global_page_state(0);
 	],[
 		AC_MSG_RESULT(yes)
@@ -1327,7 +1332,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_FREE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_FREE_PAGES;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1354,7 +1359,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_INACTIVE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1368,7 +1373,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_INACTIVE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE_ANON;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1382,7 +1387,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_INACTIVE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE_FILE;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1409,7 +1414,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_ACTIVE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1423,7 +1428,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_ACTIVE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE_ANON;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1437,7 +1442,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_ACTIVE], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/mm.h>
 	],[
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE_FILE;
 	],[
 		AC_MSG_RESULT(yes)
@@ -1604,7 +1609,7 @@ AC_DEFUN([SPL_AC_CRED_STRUCT], [
 	SPL_LINUX_TRY_COMPILE([
 		#include <linux/cred.h>
 	],[
-		struct cred *cr;
+		struct cred *cr __attribute__ ((unused));
 		cr  = NULL;
 	],[
 		AC_MSG_RESULT(yes)
diff --git a/configure b/configure
index f8dbd64657..6a322ce4ed 100755
--- a/configure
+++ b/configure
@@ -11989,7 +11989,7 @@ int
 main (void)
 {
 
-		atomic64_t *ptr;
+		atomic64_t *ptr __attribute__ ((unused));
 
   ;
   return 0;
@@ -12232,7 +12232,7 @@ int
 main (void)
 {
 
-		uintptr_t *ptr;
+		uintptr_t *ptr __attribute__ ((unused));
 
   ;
   return 0;
@@ -12296,7 +12296,7 @@ int
 main (void)
 {
 
-		struct work_struct work;
+		struct work_struct work __attribute__ ((unused));
 		INIT_WORK(&work, NULL, NULL);
 
   ;
@@ -12361,7 +12361,7 @@ int
 main (void)
 {
 
-		return register_sysctl_table(NULL,0);
+		(void) register_sysctl_table(NULL, 0);
 
   ;
   return 0;
@@ -12563,7 +12563,7 @@ int
 main (void)
 {
 
-		struct nameidata nd;
+		struct nameidata nd __attribute__ ((unused));
 
 		nd.path.mnt = NULL;
 		nd.path.dentry = NULL;
@@ -12738,7 +12738,7 @@ int
 main (void)
 {
 
-		struct ctl_table ctl;
+		struct ctl_table ctl __attribute__ ((unused));
 		ctl.ctl_name = 0;
 
   ;
@@ -13124,7 +13124,9 @@ int
 main (void)
 {
 
-		struct timespec a, b, c = { 0 };
+		struct timespec a = { 0 };
+		struct timespec b = { 0 };
+		struct timespec c __attribute__ ((unused));
 		c = timespec_sub(a, b);
 
   ;
@@ -13190,7 +13192,8 @@ int
 main (void)
 {
 
-		struct new_utsname *a = init_utsname();
+		struct new_utsname *a __attribute__ ((unused));
+		a = init_utsname();
 
   ;
   return 0;
@@ -13328,7 +13331,8 @@ main (void)
 {
 
 		struct files_struct *files = current->files;
-		struct fdtable *fdt = files_fdtable(files);
+		struct fdtable *fdt __attribute__ ((unused));
+		fdt = files_fdtable(files);
 
   ;
   return 0;
@@ -13461,7 +13465,8 @@ int
 main (void)
 {
 
-		void *a = kmalloc_node(1, GFP_KERNEL, 0);
+		void *a __attribute__ ((unused));
+		a = kmalloc_node(1, GFP_KERNEL, 0);
 
   ;
   return 0;
@@ -13634,7 +13639,7 @@ int
 main (void)
 {
 
-		struct mutex mtx;
+		struct mutex mtx __attribute__ ((unused));
 		mtx.owner = NULL;
 
   ;
@@ -14096,7 +14101,7 @@ int
 main (void)
 {
 
-		unsigned long state;
+		unsigned long state __attribute__ ((unused));
 		state = global_page_state(0);
 
   ;
@@ -14162,7 +14167,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_FREE_PAGES;
 
   ;
@@ -14228,7 +14233,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE;
 
   ;
@@ -14293,7 +14298,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE_ANON;
 
   ;
@@ -14358,7 +14363,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE_FILE;
 
   ;
@@ -14424,7 +14429,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE;
 
   ;
@@ -14489,7 +14494,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE_ANON;
 
   ;
@@ -14554,7 +14559,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE_FILE;
 
   ;
@@ -15080,7 +15085,7 @@ int
 main (void)
 {
 
-		struct cred *cr;
+		struct cred *cr __attribute__ ((unused));
 		cr  = NULL;
 
   ;
@@ -15957,7 +15962,7 @@ int
 main (void)
 {
 
-		atomic64_t *ptr;
+		atomic64_t *ptr __attribute__ ((unused));
 
   ;
   return 0;
@@ -16200,7 +16205,7 @@ int
 main (void)
 {
 
-		uintptr_t *ptr;
+		uintptr_t *ptr __attribute__ ((unused));
 
   ;
   return 0;
@@ -16264,7 +16269,7 @@ int
 main (void)
 {
 
-		struct work_struct work;
+		struct work_struct work __attribute__ ((unused));
 		INIT_WORK(&work, NULL, NULL);
 
   ;
@@ -16329,7 +16334,7 @@ int
 main (void)
 {
 
-		return register_sysctl_table(NULL,0);
+		(void) register_sysctl_table(NULL, 0);
 
   ;
   return 0;
@@ -16531,7 +16536,7 @@ int
 main (void)
 {
 
-		struct nameidata nd;
+		struct nameidata nd __attribute__ ((unused));
 
 		nd.path.mnt = NULL;
 		nd.path.dentry = NULL;
@@ -16706,7 +16711,7 @@ int
 main (void)
 {
 
-		struct ctl_table ctl;
+		struct ctl_table ctl __attribute__ ((unused));
 		ctl.ctl_name = 0;
 
   ;
@@ -17092,7 +17097,9 @@ int
 main (void)
 {
 
-		struct timespec a, b, c = { 0 };
+		struct timespec a = { 0 };
+		struct timespec b = { 0 };
+		struct timespec c __attribute__ ((unused));
 		c = timespec_sub(a, b);
 
   ;
@@ -17158,7 +17165,8 @@ int
 main (void)
 {
 
-		struct new_utsname *a = init_utsname();
+		struct new_utsname *a __attribute__ ((unused));
+		a = init_utsname();
 
   ;
   return 0;
@@ -17296,7 +17304,8 @@ main (void)
 {
 
 		struct files_struct *files = current->files;
-		struct fdtable *fdt = files_fdtable(files);
+		struct fdtable *fdt __attribute__ ((unused));
+		fdt = files_fdtable(files);
 
   ;
   return 0;
@@ -17429,7 +17438,8 @@ int
 main (void)
 {
 
-		void *a = kmalloc_node(1, GFP_KERNEL, 0);
+		void *a __attribute__ ((unused));
+		a = kmalloc_node(1, GFP_KERNEL, 0);
 
   ;
   return 0;
@@ -17602,7 +17612,7 @@ int
 main (void)
 {
 
-		struct mutex mtx;
+		struct mutex mtx __attribute__ ((unused));
 		mtx.owner = NULL;
 
   ;
@@ -18064,7 +18074,7 @@ int
 main (void)
 {
 
-		unsigned long state;
+		unsigned long state __attribute__ ((unused));
 		state = global_page_state(0);
 
   ;
@@ -18130,7 +18140,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_FREE_PAGES;
 
   ;
@@ -18196,7 +18206,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE;
 
   ;
@@ -18261,7 +18271,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE_ANON;
 
   ;
@@ -18326,7 +18336,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_INACTIVE_FILE;
 
   ;
@@ -18392,7 +18402,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE;
 
   ;
@@ -18457,7 +18467,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE_ANON;
 
   ;
@@ -18522,7 +18532,7 @@ int
 main (void)
 {
 
-		enum zone_stat_item zsi;
+		enum zone_stat_item zsi __attribute__ ((unused));
 		zsi = NR_ACTIVE_FILE;
 
   ;
@@ -19048,7 +19058,7 @@ int
 main (void)
 {
 
-		struct cred *cr;
+		struct cred *cr __attribute__ ((unused));
 		cr  = NULL;
 
   ;