Silence various sparse warnings

... related to __INT_MAX__ and friends not being defined, and various
__builtin.. function declarations missing (they should probably be added
to sparse, but I am lazy).

src/osdep/stub.h

@@ -3,6 +3,7 @@
 
 #include <ctype.h>
 #include <string.h>
+
 #if 0
 #ifdef CONFIG_DEBUG
 #define CONFIG_OWN_LIBC
@@ -144,4 +145,18 @@ int elinks_raise(int signal);
 const char *elinks_inet_ntop(int af, const void *src, char *dst, size_t size);
 #endif
 
+/* Silence various sparse warnings. */
+
+#ifndef __builtin_stpcpy
+extern char *__builtin_stpcpy(char *dest, const char *src);
+#endif
+
+#ifndef __builtin_mempcpy
+extern void *__builtin_mempcpy(void *dest, const void *src, size_t n);
+#endif
+
+#ifndef __builtin_va_copy
+#define __builtin_va_copy(dest, src) do { dest = src; } while (0)
+#endif
+
 #endif

src/osdep/types.h

@@ -107,4 +107,15 @@ typedef unsigned long long uint32_t;
 #define longlong long
 #endif
 
+/* These are mostly for shutting up sparse warnings. */
+#ifndef __INT_MAX__
+#define __INT_MAX__ 0x7fffffff
+#endif
+#ifndef __LONG_MAX__
+#define __LONG_MAX__ 0x7fffffff
+#endif
+#ifndef __SHRT_MAX__
+#define __SHRT_MAX__ 0x7fff
+#endif
+
 #endif