configure: CMake: Add -no-prefix option

Introduce a new -no-prefix option that can be used to build Qt without
having to install it.

Currently, -no-prefix is already implied by -developer-build, but
-developer-build also implies -warnings-are-errors and
-feature-private-tests, which not everyone might want to use.

Some Qt builders likely use -developer-build for the no-prefix
behavior, hence we introduce a standalone -no-prefix option to offer
a nicer user experience without -Werror and friends.

Previously it was possible to achieve the same by specifying
-prefix $PWD, but that relies on $PWD expanding property in the used
shell.

The new -no-prefix doesn't depend on the type of the shell and
is shorter to type.

Internally this gets passed by configure as -DINPUT_no_prefix=yes to
CMake, and transformed into a -DQT_FEATURE_no_prefix=ON feature.

The feature also gets automatically auto-detected to ON if
developer-build is set, -prefix is either unset or $PWD.

CMake code should still query QT_WILL_INSTALL to decide whether
files need to be installed or not.

As a drive-by, we now also export QT_FEATURE_developer_build to
be available for querying during configuration of other repos
(previously it was only possible to query FEATURE_developer_build).

Pick-to: 6.2 6.3
Change-Id: Iaa6c8d8ae2b736282e9949d2a5d7f412e290a253
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>

1 files changed, 12 insertions, 1 deletions

diff --git a/cmake/QtSetup.cmake b/cmake/QtSetup.cmake
index 87d3ad9cf8..58f723e4de 100644
--- a/cmake/QtSetup.cmake
+++ b/cmake/QtSetup.cmake
@@ -11,6 +11,13 @@ if(NOT FEATURE_developer_build AND INPUT_developer_build
     set(FEATURE_developer_build ON)
 endif()
 
+# Pre-calculate the no_prefix feature if it's set by configure via INPUT_no_prefix.
+# This needs to be done before qtbase/configure.cmake is processed.
+if(NOT FEATURE_no_prefix AND INPUT_no_prefix
+        AND NOT "${INPUT_no_prefix}" STREQUAL "undefined")
+    set(FEATURE_no_prefix ON)
+endif()
+
 set(_default_build_type "Release")
 if(FEATURE_developer_build)
     set(_default_build_type "Debug")
@@ -95,7 +102,11 @@ set(CMAKE_LINK_DEPENDS_NO_SHARED ON)
 # QtBuildInternalsExtra.cmake file.
 if (PROJECT_NAME STREQUAL "QtBase" AND NOT QT_BUILD_STANDALONE_TESTS)
     if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
-        if(FEATURE_developer_build)
+        # Handle both FEATURE_ and QT_FEATURE_ cases when they are specified on the command line
+        # explicitly. It's possible for one to be set, but not the other, because
+        # qtbase/configure.cmake is not processed by this point.
+        if(FEATURE_developer_build OR QT_FEATURE_developer_build
+            OR FEATURE_no_prefix OR QT_FEATURE_no_prefix)
             # Handle non-prefix builds by setting the CMake install prefix to point to qtbase's
             # build dir. While building another repo (like qtsvg) the CMAKE_PREFIX_PATH should be
             # set on the command line to point to the qtbase build dir.