cmake: Remove some more dead gunk

We no longer check for in tree builds anywhere (tests set up their own
tmpdir),
and we no longer support xcode.

CMakeLists.txt

@@ -7,9 +7,6 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 set(DEFAULT_BUILD_TYPE "RelWithDebInfo")
 
-# Generate Xcode schemas (but not for tests).
-set(CMAKE_XCODE_GENERATE_SCHEME 1)
-
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
     message(STATUS "Setting build type to default '${DEFAULT_BUILD_TYPE}'")
     set(CMAKE_BUILD_TYPE "${DEFAULT_BUILD_TYPE}")
@@ -17,7 +14,6 @@ endif()
 
 # Set up standard directories.
 include(GNUInstallDirs)
-add_definitions(-D_UNICODE=1)
 
 include(cmake/gettext.cmake)
 
@@ -30,12 +26,6 @@ include(cmake/Rust.cmake)
 # Work around issue where archive-built libs go in the wrong place.
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR})
 
-if(CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_CURRENT_BINARY_DIR)
-  set(FISH_IN_TREE_BUILD TRUE)
-else()
-  set(FISH_IN_TREE_BUILD FALSE)
-endif()
-
 # Set up the machinery around FISH-BUILD-VERSION-FILE
 # This defines the FBVF variable.
 include(Version)