ci: rename build setup scripts

Rename our build setup scripts to include the `build` name so that we
can add additional CI setup scripts with no ambiguity.

.github/workflows/main.yml

@@ -214,7 +214,7 @@ jobs:
         path: source
         fetch-depth: 0
     - name: Set up build environment
-      run: source/ci/setup-${{ matrix.platform.setup-script }}.sh
+      run: source/ci/setup-${{ matrix.platform.setup-script }}-build.sh
       shell: bash
       if: matrix.platform.setup-script != ''
     - name: Setup QEMU

.github/workflows/nightly.yml

@@ -271,7 +271,7 @@ jobs:
         path: source
         fetch-depth: 0
     - name: Set up build environment
-      run: source/ci/setup-${{ matrix.platform.setup-script }}.sh
+      run: source/ci/setup-${{ matrix.platform.setup-script }}-build.sh
       shell: bash
       if: matrix.platform.setup-script != ''
     - name: Setup QEMU

ci/setup-mingw.sh → ci/setup-mingw-build.sh

-#!/bin/sh -e
+#!/bin/sh
+
+set -ex
 
 echo "##############################################################################"
 echo "## Downloading mingw"

ci/setup-osx.sh → ci/setup-osx-build.sh

 #!/bin/sh
 
-set -x
+set -ex
 
 brew update
 brew install pkgconfig zlib curl openssl libssh2 ninja