add brk_ → _BRK_ to the header files declaring system calls for ape.
delete private declarations.

Reference: /n/atom/patch/applied2013/apebrk
Date: Thu Aug  1 04:56:12 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/ape/lib/ap/plan9/sys9.h	Thu Aug  1 04:55:10 2013
+++ /sys/src/ape/lib/ap/plan9/sys9.h	Thu Aug  1 04:55:10 2013
@@ -77,7 +77,6 @@
 extern	int	_AWAIT(char*, int);
 extern	int	_ALARM(unsigned long);
 extern	int	_BIND(const char*, const char*, int);
-extern	int	_BRK_(void*);
 extern	int	_CHDIR(const char*);
 extern	int	_CLOSE(int);
 extern	int	_CREATE(char*, int, unsigned long);
--- /sys/src/ape/lib/9/libc.h	Thu Aug  1 04:55:12 2013
+++ /sys/src/ape/lib/9/libc.h	Thu Aug  1 04:55:12 2013
@@ -70,7 +70,6 @@
 extern	int	_AWAIT(char*, int);
 extern	int	_ALARM(unsigned long);
 extern	int	_BIND(const char*, const char*, int);
-extern	int	_BRK_(void*);
 extern	int	_CHDIR(const char*);
 extern	int	_CLOSE(int);
 extern	int	_CREATE(char*, int, unsigned long);
--- /sys/src/ape/lib/ap/plan9/brk.c	Thu Aug  1 04:55:14 2013
+++ /sys/src/ape/lib/ap/plan9/brk.c	Thu Aug  1 04:55:14 2013
@@ -5,6 +5,7 @@
 
 char	end[];
 static	char	*bloc = { end };
+extern	int	_BRK_(void*);
 
 enum
 {