trivial: fix warnings in release builds

libsel4simple-default/src/libsel4simple-default.c

diff --git a/libsel4simple-default/src/libsel4simple-default.c b/libsel4simple-default/src/libsel4simple-default.c
index 493dcd5..d1d87ed 100644
--- a/libsel4simple-default/src/libsel4simple-default.c
+++ b/libsel4simple-default/src/libsel4simple-default.c
@@ -206,8 +206,7 @@
         ZF_LOGE("Data is null!");
     }
 
-    seL4_BootInfo *info = (seL4_BootInfo *)data;
-    debug_print_bootinfo(info);
+    debug_print_bootinfo((seL4_BootInfo *) data);
 }
 
 void simple_default_init_bootinfo(simple_t *simple, seL4_BootInfo *bi) {

libsel4utils/src/vspace/vspace.c

diff --git a/libsel4utils/src/vspace/vspace.c b/libsel4utils/src/vspace/vspace.c
index ffecede..ec0a225 100644
--- a/libsel4utils/src/vspace/vspace.c
+++ b/libsel4utils/src/vspace/vspace.c
@@ -132,7 +132,7 @@
 {
     assert(reservation != NULL);
 
-    int error;
+    UNUSED int error;
     reservation->start = ROUND_DOWN(vaddr, PAGE_SIZE_4K);
     reservation->end = ROUND_UP(vaddr + bytes, PAGE_SIZE_4K);
 

libsel4vspace/src/vspace.c

diff --git a/libsel4vspace/src/vspace.c b/libsel4vspace/src/vspace.c
index a5e677a..ee15e5a 100644
--- a/libsel4vspace/src/vspace.c
+++ b/libsel4vspace/src/vspace.c
@@ -129,7 +129,7 @@
         return NULL;
     }
 
-    int error = vspace_new_pages_at_vaddr(vspace, vaddr, num_pages, size_bits, res);
+    UNUSED int error = vspace_new_pages_at_vaddr(vspace, vaddr, num_pages, size_bits, res);
 
     vspace_free_reservation(vspace, res);