Simplify the search for OSX_DEVELOPER_ROOT and allow it to fail if no
"/Developer" exists. When it does exist, always find a MacOSX SDK
inside it to use as the default CMAKE_OSX_SYSROOT. Otherwise set
CMAKE_OSX_SYSROOT to empty.
Drop the last use of CMAKE_OSX_SYSROOT_DEFAULT. Replace internal
platform variable CMAKE_${lang}_HAS_ISYSROOT with a more general
CMAKE_${lang}_SYSROOT_FLAG variable. If the -isysroot flag exists and
CMAKE_OSX_SYSROOT points to an SDK (not "/") then always add it to
compiler command lines. This is already done in the Xcode IDE.
Like the special case for commas, this ensures that the colon only has
special meaning as the delimiter between the identifier and the
parameters of a particular expression, but constructs such as
INCLUDE_DIRECTORIES "$<1:C:\foo>"
are legal.
This reverts commit 987e12e2f9.
GenerateTargetManifest is called by the global generator before it
creates the generator targets, so we can't move it to cmGeneratorTarget
yet.
The GNU compiler information file tests for GNU >= 3.4 because earlier
versions do not have the flag. The version number test is not valid for
Clang compiler versions, but we know Clang supports the flag.
While Clang presents an almost identical interface to GNU there will be
some differences. Split the compiler information modules to allow
separate rules for Clang. Start by loading the GNU rules but leave a
place to add Clang-specific information.
Make the EXPECTED_HASH option take only a single value instead of two to
avoid handling sub-keyword arguments. This is also consistent with
URL_HASH in ExternalProject.
This way we don't need to check the definitions from the Makefile when
generating later, and can more easily add generator expressions.
Duplication is not a problem as the definitions are de-duplicated before
generating.
Removing the Process() API and removing the parameters from the
constructor will allow cmGeneratorExpressions to be cached and evaluated
with multiple configs for example, such as when evaluating target
properties. This requires the creation of a new compiled representation
of cmGeneratorExpression. The cmListFileBacktrace remains in the
constructor so that we can record where a particular generator
expression appeared in the CMakeLists file.
The expressions may be parsed and then cached and evaluated multiple
times. They are evaluated lazily so that literals such as ',' can be
treated as universal parameter separators, and can be processed from
results without appearing literally, and without interfering with the
parsing/evaluation of the entire expression.