fix: Fix crash in static-linked linux builds

The official, static-linked linux builds were crashing in their use of
getaddrinfo, which libcurl was configured to use.  Both getaddrinfo
and all of its alternatives available in glibc fail with static
linking.

We can fix this by configuring libcurl to use libc-ares on Linux
instead.  This allows us to keep the benefits of a statically-linked
Linux binary.

Closes #996

Change-Id: Ib4a9eb939813fd165727788726459ef4adf3fc4d

.github/workflows/custom-actions/build-packager/action.yaml

@@ -43,6 +43,15 @@ runs:
           echo "::endgroup::"
         fi
 
+    - name: Install c-ares (Linux only)
+      shell: bash
+      run: |
+        if [[ "${{ runner.os }}" == "Linux" ]]; then
+          echo "::group::Install c-ares"
+          sudo apt install -y libc-ares-dev
+          echo "::endgroup::"
+        fi
+
     - name: Install depot tools
       shell: bash
       run: |

docs/source/build_instructions.md

@@ -12,6 +12,7 @@ for [other distros below](#notes-for-other-linux-distros).
 sudo apt-get update
 sudo apt-get install -y \
         curl \
+        libc-ares-dev \
         build-essential git python python3
 ```
 
@@ -243,7 +244,7 @@ Use `apk` command to install dependencies:
 ```shell
 apk add --no-cache \
         bash curl \
-        bsd-compat-headers linux-headers \
+        bsd-compat-headers c-ares-dev linux-headers \
         build-base git ninja python2 python3
 ```
 
@@ -270,6 +271,7 @@ Instead of running `sudo apt-get install` to install build dependencies, run:
 ```shell
 sudo pacman -Sy --needed \
         core/which \
+        c-ares \
         gcc git python2 python3
 ```
 
@@ -284,7 +286,7 @@ Instead of running `sudo apt-get install` to install build dependencies, run:
 ```shell
 su -c 'yum install -y \
         which \
-        libatomic \
+        c-ares-devel libatomic \
         gcc-c++ git python2'
 ```
 
@@ -299,6 +301,7 @@ Use `zypper` command to install dependencies:
 ```shell
 sudo zypper in -y \
         curl which \
+        c-ares-devel \
         gcc-c++ git python python3
 ```
 

packager/testing/dockers/Alpine_Dockerfile

@@ -3,7 +3,7 @@ FROM alpine:3.11
 # Install utilities, libraries, and dev tools.
 RUN apk add --no-cache \
         bash curl \
-        bsd-compat-headers linux-headers \
+        bsd-compat-headers c-ares-dev linux-headers \
         build-base git ninja python2 python3
 
 # Install depot_tools.

packager/testing/dockers/ArchLinux_Dockerfile

@@ -3,6 +3,7 @@ FROM archlinux:latest
 # Install utilities, libraries, and dev tools.
 RUN pacman -Sy --needed --noconfirm \
         core/which \
+        c-ares \
         gcc git python2 python3
 
 # Install depot_tools.

packager/testing/dockers/CentOS_Dockerfile

@@ -3,7 +3,7 @@ FROM centos:8
 # Install utilities, libraries, and dev tools.
 RUN yum install -y \
         which \
-        libatomic \
+        c-ares-devel libatomic \
         gcc-c++ git python2 python3
 
 # Default to python3.

packager/testing/dockers/Debian_Dockerfile

@@ -4,6 +4,7 @@ FROM debian:9
 RUN apt-get update && apt-get install -y apt-utils
 RUN apt-get install -y \
         curl \
+        libc-ares-dev \
         build-essential git python python3
 
 # Install depot_tools.

packager/testing/dockers/Fedora_Dockerfile

@@ -3,7 +3,7 @@ FROM fedora:34
 # Install utilities, libraries, and dev tools.
 RUN yum install -y \
         which \
-        libatomic \
+        c-ares-devel libatomic \
         gcc-c++ git python2
 
 # Default to python3.

packager/testing/dockers/OpenSUSE_Dockerfile

@@ -3,6 +3,7 @@ FROM opensuse/leap:15
 # Install utilities, libraries, and dev tools.
 RUN zypper in -y \
         curl which \
+        c-ares-devel \
         gcc-c++ git python python3
 
 # Install depot_tools.

packager/testing/dockers/Ubuntu_Dockerfile

@@ -4,6 +4,7 @@ FROM ubuntu:18.04
 RUN apt-get update && apt-get install -y apt-utils
 RUN apt-get install -y \
         curl \
+        libc-ares-dev \
         build-essential git python python3
 
 # Install depot_tools.

packager/third_party/curl/curl.gyp

@@ -37,10 +37,16 @@
               'HAVE_CONFIG_H',
               'CURL_CA_BUNDLE="<!(config/linux/find_curl_ca_bundle.sh)"',
               'USE_OPENSSL',
+              'USE_ARES',
             ],
             'include_dirs': [
               'config/linux',
             ],
+            'link_settings': {
+              'libraries': [
+                '-lcares',
+              ],
+            },
           },
         }],
         ['OS == "mac"', {