Create breakpoint.h with decls related to breakpoints
diff --git a/sysdeps/linux-gnu/breakpoint.c b/sysdeps/linux-gnu/breakpoint.c
index 5a49e9d..bbfa481 100644
--- a/sysdeps/linux-gnu/breakpoint.c
+++ b/sysdeps/linux-gnu/breakpoint.c
@@ -5,6 +5,7 @@
 
 #include "common.h"
 #include "arch.h"
+#include "breakpoint.h"
 
 #ifdef ARCH_HAVE_ENABLE_BREAKPOINT
 extern void arch_enable_breakpoint(pid_t, Breakpoint *);
diff --git a/sysdeps/linux-gnu/events.c b/sysdeps/linux-gnu/events.c
index b6c12ef..79f6817 100644
--- a/sysdeps/linux-gnu/events.c
+++ b/sysdeps/linux-gnu/events.c
@@ -12,6 +12,7 @@
 #include <unistd.h>
 
 #include "common.h"
+#include "breakpoint.h"
 
 static Event event;
 
diff --git a/sysdeps/linux-gnu/proc.c b/sysdeps/linux-gnu/proc.c
index a99593c..d8d381a 100644
--- a/sysdeps/linux-gnu/proc.c
+++ b/sysdeps/linux-gnu/proc.c
@@ -17,6 +17,7 @@
 #include <sys/syscall.h>
 #include <error.h>
 
+#include "breakpoint.h"
 
 /* /proc/pid doesn't exist just after the fork, and sometimes `ltrace'
  * couldn't open it to find the executable.  So it may be necessary to
diff --git a/sysdeps/linux-gnu/trace.c b/sysdeps/linux-gnu/trace.c
index d962048..0751a35 100644
--- a/sysdeps/linux-gnu/trace.c
+++ b/sysdeps/linux-gnu/trace.c
@@ -16,6 +16,7 @@
 
 #include "ptrace.h"
 #include "common.h"
+#include "breakpoint.h"
 
 /* If the system headers did not provide the constants, hard-code the normal
    values.  */