Work around newlib build problems with gcc14

--- xen-4.18.0/stubdom/Makefile.orig	2024-01-15 20:35:36.941740548 +0000
+++ xen-4.18.0/stubdom/Makefile	2024-01-29 22:29:29.067367523 +0000
@@ -45,6 +45,7 @@
 NEWLIB_CFLAGS+=-D_I386MACH_ALLOW_HW_INTERRUPTS
 STUBDOM_SUPPORTED=1
 endif
+NEWLIB_CFLAGS+=-Wno-error=implicit-function-declaration
 
 CROSS_ROOT=cross-root-$(GNU_TARGET_ARCH)
 CROSS_PREFIX=$(CURDIR)/$(CROSS_ROOT)
--- xen-4.18.0/extras/mini-os/include/posix/sys/mman.h.orig	2022-07-04 09:52:38.000000000 +0100
+++ xen-4.18.0/extras/mini-os/include/posix/sys/mman.h	2024-02-01 23:00:19.923263409 +0000
@@ -16,7 +16,7 @@
 
 void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset) asm("mmap64");
 int munmap(void *start, size_t length);
-static inline mlock(const void *addr, size_t len) { return 0; }
-static inline munlock(const void *addr, size_t len) { return 0; }
+static inline int mlock(const void *addr, size_t len) { return 0; }
+static inline int munlock(const void *addr, size_t len) { return 0; }
 
 #endif /* _POSIX_SYS_MMAN_H */