tidy-up: LibreSSL Git repository URLs and local CI builds

Also:
- point the source tarball to a working URL.
  The GitHub release page misses the official source tarball for 4.1.1.
- GHA/linux: switch LibreSSL build to cmake (syncing with http3-linux.)
- GHA/macos: drop no longer needed LibreSSL build workaround.

Closes #18792

.github/workflows/macos.yml

@@ -58,7 +58,7 @@ jobs:
       LDFLAGS: ''
       MATRIX_BUILD: ${{ matrix.build.generate && 'cmake' || 'autotools' }}
       MATRIX_OPTIONS: ${{ matrix.build.options }}
-      # renovate: datasource=github-tags depName=libressl-portable/portable versioning=semver registryUrl=https://github.com
+      # renovate: datasource=github-tags depName=libressl/portable versioning=semver registryUrl=https://github.com
       LIBRESSL_VERSION: 4.1.1
     strategy:
       fail-fast: false
@@ -124,9 +124,7 @@ jobs:
           curl --disable --fail --silent --show-error --connect-timeout 15 --max-time 60 --retry 3 --retry-connrefused \
             --location "https://github.com/libressl/portable/releases/download/v${LIBRESSL_VERSION}/libressl-${LIBRESSL_VERSION}.tar.gz" | tar -x
           cd "libressl-${LIBRESSL_VERSION}"
-          # FIXME: on the 4.0.1 release, delete '-DHAVE_ENDIAN_H=0'
           cmake -B . -G Ninja \
-            -DHAVE_ENDIAN_H=0 \
             -DCMAKE_INSTALL_PREFIX=/Users/runner/libressl \
             -DCMAKE_SYSTEM_NAME=iOS \
             -DCMAKE_SYSTEM_PROCESSOR=aarch64 \