Remove cat_ignore_eagain (#9531)

Summary:
... since it was only necessary to work around a bug on certain Ubuntu
16.04 images (and we now use 20.04 across the board).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9531

Test Plan: Watch CI.

Reviewed By: ajkr

Differential Revision: D34089424

Pulled By: ltamasi

fbshipit-source-id: f15f86332c119099f61b9bdc74604657fc5d964e

.circleci/cat_ignore_eagain

@@ -1,54 +0,0 @@
-#! /bin/bash
-
-# Work around issue with parallel make output causing random error, as in
-# make[1]: write error: stdout
-# Probably due to a kernel bug:
-#   https://bugs.launchpad.net/ubuntu/+source/linux-signed/+bug/1814393
-# Seems to affect image ubuntu-1604:201903-01 and ubuntu-1604:202004-01
-
-cd "$(dirname $0)"
-
-if [ ! -x cat_ignore_eagain.out ]; then
-    cc -x c -o cat_ignore_eagain.out - << EOF
-#include <unistd.h>
-#include <errno.h>
-#include <stdio.h>
-int main() {
-    int n, m, p;
-    char buf[1024];
-    for (;;) {
-        n = read(STDIN_FILENO, buf, 1024);
-        if (n > 0 && n <= 1024) {
-            for (m = 0; m < n;) {
-                p = write(STDOUT_FILENO, buf + m, n - m);
-                if (p < 0) {
-                    if (errno == EAGAIN) {
-                        // ignore but pause a bit
-                        usleep(100);
-                    } else {
-                        perror("write failed");
-                        return 42;
-                    }
-                } else {
-                    m += p;
-                }
-            }
-        } else if (n < 0) {
-            if (errno == EAGAIN) {
-                // ignore but pause a bit
-                usleep(100);
-            } else {
-                // Some non-ignorable error
-                perror("read failed");
-                return 43;
-            }
-        } else {
-            // EOF
-            return 0;
-        }
-    }
-}
-EOF
-fi
-
-exec ./cat_ignore_eagain.out

.circleci/config.yml

@@ -361,7 +361,7 @@ jobs:
     steps:
       - pre-steps
       - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-7 g++-7 libgflags-dev
-      - run: CC=gcc-7 CXX=g++-7 V=1 make -j32 check 2>&1 | .circleci/cat_ignore_eagain
+      - run: CC=gcc-7 CXX=g++-7 V=1 make -j32 check
       - post-steps
 
   build-linux-gcc-8-no_test_run:
@@ -371,7 +371,7 @@ jobs:
     steps:
       - pre-steps
       - run: sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test && sudo apt-get update -y && sudo apt-get install gcc-8 g++-8 libgflags-dev
-      - run: CC=gcc-8 CXX=g++-8 V=1 make -j8 all 2>&1 | .circleci/cat_ignore_eagain
+      - run: CC=gcc-8 CXX=g++-8 V=1 make -j8 all
       - post-steps
 
   build-linux-gcc-10-cxx20-no_test_run: