mmap: add include for cerrno (#11296)

ggml-ci

Co-authored-by: Xuan Son Nguyen <son@huggingface.co>

src/llama-mmap.cpp

@@ -7,6 +7,7 @@
 #include <cstring>
 #include <climits>
 #include <stdexcept>
+#include <cerrno>
 
 #ifdef __has_include
     #if __has_include(<unistd.h>)