cross-build: fix some redeclaration warnings during bootstrap

MFC after:	3 days

tools/build/cross-build/include/linux/stdio.h

@@ -37,13 +37,17 @@
  */
 
 /* No #pragam once since glibc can include this multiple times */
-#include <sys/cdefs.h>
-
 #include_next <stdio.h>
 
+#ifndef _BOOTSTRAP_LINUX_STDIO_H
+#define _BOOTSTRAP_LINUX_STDIO_H
+#include <sys/cdefs.h>
+
 __BEGIN_DECLS
 char *fgetln(FILE *, __SIZE_TYPE__ *);
 #if defined(_WCHAR_H)
 __WCHAR_TYPE__ *fgetwln(FILE *__restrict, __SIZE_TYPE__ *__restrict);
 #endif
 __END_DECLS
+
+#endif

tools/build/cross-build/include/linux/stdlib.h

@@ -60,8 +60,6 @@ int cgetustr(char *, const char *, char **);
 const char *getprogname(void);
 void setprogname(const char *progname);
 
-void *reallocarray(void *, size_t, size_t) __result_use_check
-    __alloc_size2(2, 3);
 void *reallocf(void *, size_t) __result_use_check __alloc_size(2);
 
 unsigned arc4random(void);

tools/build/cross-build/include/linux/sys/param.h

@@ -47,6 +47,3 @@
  * let's use 32 since that will work across all systems
  */
 #define MAXLOGNAME 33 /* max login name length (incl. NUL) */
-
-/* For elftoolchain (seems like on ubuntu it's in errno.h) */
-extern char *program_invocation_short_name;

tools/build/cross-build/include/linux/unistd.h

@@ -85,10 +85,6 @@ getentropy(void *buf, size_t buflen)
 }
 #endif
 
-/* Used by elftoolchain: */
-extern char *program_invocation_name;
-extern char *program_invocation_short_name;
-
 void *setmode(const char *);
 mode_t getmode(const void *, mode_t);
 

tools/build/cross-build/include/mac/stdlib.h

@@ -45,6 +45,4 @@ int rpmatch(const char *response);
 long long strtonum(const char *numstr, long long minval, long long maxval,
     const char **errstrp);
 
-void *reallocarray(void *optr, size_t nmemb, size_t size);
-
 __END_DECLS