Fixed counting of sent bytes in the send chain functions on EINTR.

Previously, a value of the "send" variable wasn't properly adjusted
in a rare case when syscall was interrupted by a signal.  As a result,
these functions could send less data than the limit allows.

src/os/unix/ngx_darwin_sendfile_chain.c

diff --git a/src/os/unix/ngx_darwin_sendfile_chain.c b/src/os/unix/ngx_darwin_sendfile_chain.c
index dd574e5..8485f97 100644
--- a/src/os/unix/ngx_darwin_sendfile_chain.c
+++ b/src/os/unix/ngx_darwin_sendfile_chain.c
@@ -308,6 +308,7 @@
         in = ngx_handle_sent_chain(in, sent);
 
         if (eintr) {
+            send = prev_send + sent;
             continue;
         }
 

src/os/unix/ngx_freebsd_sendfile_chain.c

diff --git a/src/os/unix/ngx_freebsd_sendfile_chain.c b/src/os/unix/ngx_freebsd_sendfile_chain.c
index f5d0f3a..88eacc2 100644
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -378,6 +378,7 @@
         }
 
         if (eintr) {
+            send = prev_send + sent;
             continue;
         }
 

src/os/unix/ngx_linux_sendfile_chain.c

diff --git a/src/os/unix/ngx_linux_sendfile_chain.c b/src/os/unix/ngx_linux_sendfile_chain.c
index 1060852..60867c5 100644
--- a/src/os/unix/ngx_linux_sendfile_chain.c
+++ b/src/os/unix/ngx_linux_sendfile_chain.c
@@ -316,6 +316,7 @@
         in = ngx_handle_sent_chain(in, sent);
 
         if (eintr) {
+            send = prev_send;
             continue;
         }
 

src/os/unix/ngx_solaris_sendfilev_chain.c

diff --git a/src/os/unix/ngx_solaris_sendfilev_chain.c b/src/os/unix/ngx_solaris_sendfilev_chain.c
index ba328c8..1b71f1d 100644
--- a/src/os/unix/ngx_solaris_sendfilev_chain.c
+++ b/src/os/unix/ngx_solaris_sendfilev_chain.c
@@ -200,6 +200,7 @@
         in = ngx_handle_sent_chain(in, sent);
 
         if (eintr) {
+            send = prev_send + sent;
             continue;
         }
 

src/os/unix/ngx_writev_chain.c

diff --git a/src/os/unix/ngx_writev_chain.c b/src/os/unix/ngx_writev_chain.c
index 95af2da..c7b6ebf 100644
--- a/src/os/unix/ngx_writev_chain.c
+++ b/src/os/unix/ngx_writev_chain.c
@@ -134,6 +134,7 @@
         in = ngx_handle_sent_chain(in, sent);
 
         if (eintr) {
+            send = prev_send;
             continue;
         }