Add CI testing on CentOS 7

.gitlab/ci/centos-7.yml

@@ -0,0 +1,22 @@
+include: '/.gitlab/ci/test-template.yml'
+
+.centos7-test-workaround:
+  extends: .unit-test
+  before_script:
+    - yum install -y make libcurl-devel
+    - git clone https://github.com/git/git -bv2.28.0 --depth 1
+    - cd git
+    - make prefix=/usr -j all install NO_OPENSSL=1 NO_EXPAT=1 NO_TCLTK=1 NO_GETTEXT=1 NO_PERL=1
+
+swift trunk:
+  extends: .centos7-test-workaround
+  image: swiftlang/swift:nightly-master-centos7
+  allow_failure: true
+
+swift 5.3:
+  extends: .centos7-test-workaround
+  image: swiftlang/swift:nightly-5.3-centos7
+
+swift 5.2:
+  extends: .centos7-test-workaround
+  image: swift:5.2-centos7

.gitlab/ci/main.yml

@@ -76,6 +76,12 @@ Ubuntu Focal:
     strategy: depend
     include: '/.gitlab/ci/ubuntu-focal.yml'
 
+CentOS 7:
+  stage: Platform Tests
+  trigger:
+    strategy: depend
+    include: '/.gitlab/ci/centos-7.yml'
+
 CentOS 8:
   stage: Platform Tests
   trigger:

README.md

@@ -115,14 +115,15 @@ The oldest version of Swift will be dropped within **3 months** of an official r
 The following table shows the combination of Swift language versions and operating systems that
 receive regular unit testing (either in development, or with CI).
 
-| Platform | Swift 5.1 | 5.2 | 5.3 | Trunk |
-|:---------|:-------:|:---:|:---:|:-----:|
-| macOS Latest | | | :white_check_mark: | |
-| Ubuntu 20.04 (Focal)  | | :white_check_mark: | | :white_check_mark: |
+| Platform              | Swift 5.1          | 5.2                | 5.3                | Trunk              |
+|:----------------------|:------------------:|:------------------:|:------------------:|:------------------:|
+| macOS Latest (Intel)  |                    |                    | :white_check_mark: |                    |
+| Ubuntu 20.04 (Focal)  |                    | :white_check_mark: |                    | :white_check_mark: |
 | Ubuntu 18.04 (Bionic) | :white_check_mark: | :white_check_mark: | :white_check_mark: | :white_check_mark: |
 | Ubuntu 16.04 (Xenial) | :white_check_mark: | :white_check_mark: | :white_check_mark: | :white_check_mark: |
-| Amazon Linux 2 | | :white_check_mark: | | :white_check_mark: |
-| CentOS 8 | | :white_check_mark: | | :white_check_mark: |
+| Amazon Linux 2        |                    | :white_check_mark: |                    | :white_check_mark: |
+| CentOS 7              |                    | :white_check_mark: | :white_check_mark: | :white_check_mark: |
+| CentOS 8              |                    | :white_check_mark: |                    | :white_check_mark: |
 
 ## License