seL4platsupport: Use strtol instead of sscanf to parse hex

libsel4platsupport/src/bootinfo.c

diff --git a/libsel4platsupport/src/bootinfo.c b/libsel4platsupport/src/bootinfo.c
index 2906035..a011f33 100644
--- a/libsel4platsupport/src/bootinfo.c
+++ b/libsel4platsupport/src/bootinfo.c
@@ -23,8 +23,8 @@
         ZF_LOGE("Attempted %s in an environment without bootinfo.", __FUNCTION__);
         return NULL;
     }
-    void *bi;
-    if (sscanf(bi_string, "%p", &bi) != 1) {
+    void *bi = (void *)strtol(bi_string, NULL, 0);
+    if (bi == 0) {
         ZF_LOGE("bootinfo environment value '%s' was not valid.", bi_string);
         return NULL;
     }