https://bugs.gentoo.org/414637

From 302e8ec6cd62912a3cd6494ce6702f4ad8dae0e2 Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@gentoo.org>
Date: Fri, 4 May 2012 19:30:59 -0400
Subject: [PATCH] util: fix building when glibc has a stub process_vm_readv

If you have a newer glibc which provides process_vm_readv, but it is built
against older kernel headers which lack __NR_process_vm_readv, the library
will contain a stub implementation that just returns ENOSYS.  Autoconf
checks for this case explicitly and will declare it as unavailable.  So we
end up in a case where the headers provide the prototype, but autoconf has
not defined HAVE_PROCESS_VM_READV, so we hit the same build failure again:

util.c:738:16: error: static declaration of 'process_vm_readv' follows non-static declaration
/usr/include/bits/uio.h:58:16: note: previous declaration of 'process_vm_readv' was here

So rename our local function to something unique, and add a define so the
callers all hit the right place.

* util.c (strace_process_vm_readv): Rename from process_vm_readv.
(process_vm_readv): Define to strace_process_vm_readv.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
 util.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/util.c b/util.c
index d347bd8..f27acdf 100644
--- a/util.c
+++ b/util.c
@@ -735,7 +735,8 @@ static bool process_vm_readv_not_supported = 0;
 
 #if defined(__NR_process_vm_readv)
 static bool process_vm_readv_not_supported = 0;
-static ssize_t process_vm_readv(pid_t pid,
+/* Have to avoid duplicating with the C library headers. */
+static ssize_t strace_process_vm_readv(pid_t pid,
 		 const struct iovec *lvec,
 		 unsigned long liovcnt,
 		 const struct iovec *rvec,
@@ -744,6 +745,7 @@ static ssize_t process_vm_readv(pid_t pid,
 {
 	return syscall(__NR_process_vm_readv, (long)pid, lvec, liovcnt, rvec, riovcnt, flags);
 }
+#define process_vm_readv strace_process_vm_readv
 #else
 static bool process_vm_readv_not_supported = 1;
 # define process_vm_readv(...) (errno = ENOSYS, -1)
-- 
1.7.9.7