CMake: Automatically use Xcode generator in qt-cmake + iOS

When calling qt-cmake on the command line, we don't usually force
usage of a particular CMake generator and defer to the user's choice
or CMake's default for the host OS.

In the case of iOS, the generator that makes the most sense to use is
Xcode. One could also use Ninja / Unix Makefiles if the project
is only building static libraries, but for shared libraries and
executables the project likely needs the code signing
provided by xcodebuild.

When targeting iOS, use a different qt-cmake file template.

The iOS-specific shell script will set the CMAKE_GENERATOR environment
variable to 'Xcode'.
If no -G or -D CMAKE_GENERATOR is provided on the command line then
the project will use the Xcode generator. Otherwise the generator
given on the command line takes precedence.

The CMAKE_GENERATOR environment variable from the parent process is
completely ignored.

The logic is only done for iOS, to reduce the likeliness
of breaking the qt-cmake script for other platforms.

Note that Qt Creator does not use qt-cmake, but rather calls cmake
directly with additional options like the toolchain file,
architecture, sysroot, etc.

[ChangeLog][iOS][CMake] qt-cmake now defaults to using the Xcode
generator when targeting iOS projects.

Pick-to: 6.2 6.3
Fixes: QTBUG-100834
Change-Id: I39b3dce47cc9ee2f98678631e4bd035c59c65294
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>

1 files changed, 22 insertions, 0 deletions

diff --git a/bin/qt-cmake.ios.in b/bin/qt-cmake.ios.in
new file mode 100755
index 0000000000..260da534d3
--- /dev/null
+++ b/bin/qt-cmake.ios.in
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+# The directory of this script is the expanded absolute path of the "$qt_prefix/bin" directory.
+script_dir_path=`dirname $0`
+script_dir_path=`(cd "$script_dir_path"; /bin/pwd)`
+
+# Try to use original cmake, otherwise to make it relocatable, use any cmake found in PATH.
+original_cmake_path="@CMAKE_COMMAND@"
+cmake_path=$original_cmake_path
+if ! test -f "$cmake_path"; then
+    cmake_path="cmake"
+fi
+
+# Find the qt toolchain relative to the absolute bin dir path where the script is located.
+toolchain_path="$script_dir_path/@__GlobalConfig_relative_path_from_bin_dir_to_cmake_config_dir@/qt.toolchain.cmake"
+
+# Specify Xcode as the default generator by assigning it to the CMAKE_GENERATOR env var.
+# An explicit -G or -D CMAKE_GENERATOR given on the command line will still take precedence.
+export CMAKE_GENERATOR=Xcode
+
+# Run cmake.
+exec "$cmake_path" -DCMAKE_TOOLCHAIN_FILE="$toolchain_path" @__qt_cmake_extra@ "$@"