Build fixes (#928)

Upgrade the slightly old`attrs` package on Travis-CI to fix reuse 4.0.2 failure
due to fsfe/reuse-tool#1039.

Update iOS deployment target to 12.0 so Xcode 15 can be used for builds.

.travis.yml

@@ -88,11 +88,6 @@ jobs:
         - CHECK_REUSE: ONLY
     - os: linux
       dist: jammy
-      addons:
-        apt:
-          packages:
-            - python3
-            - python3-venv
       compiler: gcc # clang is tested by macOS build
       env:
         # NB: This must not have the fourth component of the version number.
@@ -107,8 +102,6 @@ jobs:
         apt:
           packages:
             - graphviz
-            - python3
-            - python3-venv
       compiler: gcc
       #jdk: openjdk17 # Reminder to find correct way to select jdk 17
       env:
@@ -120,16 +113,15 @@ jobs:
           SUPPORT_SSE=ON SUPPORT_OPENCL=OFF WERROR=ON PACKAGE=YES
     - os: linux
       arch: arm64
+      dist: jammy
       # Suggested by Travis-CI support to workaround pyparser install
-      # failure with 2024.6.25 runner image.
+      # failure due to no permission to write to system packages with
+      # 2024.6.25 runner image. Forces use of previous runner version.
       group: previous
-      dist: jammy
       addons:
         apt:
           packages:
             - graphviz
-            - python3
-            - python3-venv
       compiler: gcc
       #jdk: openjdk17
       env:
@@ -220,7 +212,15 @@ install:
   linux)
     if [ "$CHECK_REUSE" = "YES" -o "$CHECK_REUSE" = "ONLY" ]; then
       set -e  # because the if below swallows a bad exit status.
+      # reuse available via `apt install reuse` is very old: 0.14.0.
+      # Therefore install via pip. Version today, 2024.7.7, is 4.0.2.
       pip3 install reuse
+      # 4.0.2's version specifier, attrs>=21.1, is too relaxed. reuse fails
+      # with ModuleNotFound for attrs. 21.2 is installed in the runner.
+      # It needs a more recent attrs. As of 2.24.7.7 this upgrades to 23.2
+      # and reuse works. Watch https://github.com/fsfe/reuse-tool/issues/1039.
+      # When fixed remove this upgrade line.
+      pip3 install --upgrade attrs
       set +e
     fi
     if [ "$CHECK_REUSE" != "ONLY" -a "$CHECK_MKVK" != "ONLY" -a "$WASM_BUILD" != "YES" ]; then

CMakeLists.txt

@@ -170,7 +170,7 @@ if(APPLE)
     if(APPLE_MAC_OS)
         set(CMAKE_OSX_DEPLOYMENT_TARGET "10.11" CACHE STRING "macOS Deployment Target")
     elseif(IOS OR CMAKE_SYSTEM_NAME STREQUAL "tvOS")
-        set(CMAKE_OSX_DEPLOYMENT_TARGET "11.0" CACHE STRING "iOS/tvOS Deployment Target")
+        set(CMAKE_OSX_DEPLOYMENT_TARGET "12.0" CACHE STRING "iOS/tvOS Deployment Target")
         set(CMAKE_XCODE_ATTRIBUTE_ONLY_ACTIVE_ARCH NO)
     elseif(CMAKE_SYSTEM_NAME STREQUAL "visionOS")
         set(CMAKE_OSX_DEPLOYMENT_TARGET "1.0" CACHE STRING "visionOS Deployment Target")