4499d50 Mark CustomCommand test perconfig.out as SYMBOLIC
f0cdb60 Introduce "generator expression" syntax to custom commands (#11209)
4749e4c Record set of targets used in cmGeneratorExpression
ef9e9de Optionally suppress errors in cmGeneratorExpression
45e1953 Factor per-config sample targets out of 'Testing' test
4091bca Factor generator expression docs out of add_test
bfb7288 Record backtrace in cmCustomCommand
One of Cygwin's goals is to build projects using the POSIX API with no
Windows awareness. Many CMake-built projects have been written to test
for UNIX and WIN32 but not CYGWIN. The preferred behavior under Cygwin
in such projects is to take the UNIX path but not the WIN32 path.
Unfortunately this change is BACKWARDS INCOMPATIBLE for Cygwin-aware
CMake projects! Some projects that previously built under Cygwin and
are Cygwin-aware when they test for WIN32 may now behave differently.
Eventually these projects will need to be updated, but to help users
build them in the meantime we print a warning about the change in
behavior. Furthermore, one may set CMAKE_LEGACY_CYGWIN_WIN32 to request
old behavior during the transition.
Normally we avoid backwards incompatible changes, but we make an
exception in this case for a few reasons:
(1) This behavior is preferred by Cygwin's design goals.
(2) A warning provides a clear path forward for everyone who may see
incompatible behavior, and CMAKE_LEGACY_CYGWIN_WIN32 provides a
compatibility option. The warning and compatibility option both
disappear when the minimum required version of CMake in a project is
sufficiently new, so this issue will simply go away over time as
projects are updated to account for the change.
(3) The fixes required to update projects are fairly insignificant.
Furthermore, the Cygwin distribution has no releases itself so project
versions that predate said fixes tend to be difficult to build anyway.
(4) This change enables many CMake-built projects that did not
previously build under Cygwin to work out-of-the-box. From bug #10122:
"I have built over 120 different source packages with (my patched)
CMake, including most of KDE4, and have found that NOT defining
WIN32 on Cygwin is much more accurate." -- Yaakov Selkowitz
A fully compatible change would require patches on top of these project
releases for Cygwin even though they otherwise need not be aware of it.
(5) Yaakov has been maintaining a fork of CMake with this change for the
Cygwin Ports distribution. It works well in practice. By accepting the
change in upstream CMake we avoid confusion between the versions.
CMake itself builds without WIN32 defined on Cygwin. Simply disable
CMAKE_LEGACY_CYGWIN_WIN32 explicitly in our own CMakeLists.txt file.
The target_link_libraries command requires its first argument to be a
target in the current directory. Document this and update the error
message to be more specific. While at it, format the error message with
a call stack.
Commit e01cce28 (Allow add_dependencies() on imported targets,
2010-11-19) started using cmMakefile::FindTargetToUse to follow
dependencies, including those of GLOBAL_TARGETs like INSTALL and
PACKAGE. Since global targets exist in every directory, dependencies
between them must be traced within each directory too.
Teach FindTargetToUse to check the current directory before checking
globally. For global targets this will find the local copy. For for
normal targets this will be a no-op because they are globally unique.
Factor out reading of CMAKE_CONFIGURATION_TYPES and CMAKE_BUILD_TYPE
into cmMakefile::GetConfigurations. Read the former only in
multi-config generators.
