configure: check for mprotect

Signed-off-by: Mans Rullgard <mans@mansr.com>

configure

@@ -1198,6 +1198,7 @@ HAVE_LIST="
     mkstemp
     mm_empty
     mmap
+    mprotect
     msvcrt
     nanosleep
     poll_h
@@ -3202,6 +3203,7 @@ check_func  localtime_r
 check_func  ${malloc_prefix}memalign            && enable memalign
 check_func  mkstemp
 check_func  mmap
+check_func  mprotect
 check_func  ${malloc_prefix}posix_memalign      && enable posix_memalign
 check_func_headers malloc.h _aligned_malloc     && enable aligned_malloc
 check_func  setrlimit