Remove Travis-CI and AppVeyor configuration files and test old compiler versions.

.github/workflows/ci.yml

@@ -13,9 +13,10 @@ jobs:
     test:
         name: CI
         strategy:
+            fail-fast: false
             matrix:
                 os: [ubuntu-latest, windows-latest, macOS-latest]
-                dc: [dmd-latest, ldc-latest]
+                dc: [dmd-latest, ldc-latest, dmd-2.079.0, ldc-1.9.0, ldc-1.17.0]
                 arch: [x86_64]
                 config: [select, epoll, cfrunloop, winapi]
                 exclude:
@@ -25,6 +26,14 @@ jobs:
                   - {os: macOS-latest, config: winapi}
                   - {os: windows-latest, config: cfrunloop}
                   - {os: windows-latest, config: epoll}
+                  # macOS fails up to FE 2.086.x, so we test on a slightly newer
+                  # version instead
+                  # "dyld: lazy symbol binding failed: Symbol not found: _dyld_enumerate_tlv_storage"
+                  - {os: macOS-latest, dc: dmd-2.079.0}
+                  - {os: macOS-latest, dc: ldc-1.9.0}
+                  - {os: windows-latest, dc: ldc-1.9.0, config: select}
+                  - {os: windows-latest, dc: ldc-1.17.0}
+                  - {os: ubuntu-latest, dc: ldc-1.17.0}
 
         runs-on: ${{ matrix.os }}
         steps:
@@ -38,5 +47,6 @@ jobs:
             - name: Run tests
               env:
                 CONFIG: ${{matrix.config}}
+                ARCH: ${{matrix.arch}}
               shell: bash
-              run: ./travis-ci.sh
+              run: ./run-ci.sh