build: simplify system checks (NFC)

CMake 3.25 introduced a more consistent way to check what system is
being built for. Adopt that uniformly through the build to make it
easier to understand.

Author: compnerd

CMakeLists.txt

@@ -9,7 +9,7 @@ project(dispatch
 
 set(CMAKE_POSITION_INDEPENDENT_CODE YES)
 
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
   include(CheckCSourceCompiles)
   include(CheckSymbolExists)
 
@@ -128,7 +128,7 @@ set(USE_LIBDISPATCH_INIT_CONSTRUCTOR ${ENABLE_DISPATCH_INIT_CONSTRUCTOR})
 
 option(ENABLE_DTRACE "enable dtrace support" "")
 
-if(CMAKE_SYSTEM_NAME STREQUAL Darwin OR CMAKE_SYSTEM_NAME STREQUAL FreeBSD)
+if(APPLE OR BSD)
   set(ENABLE_INTERNAL_PTHREAD_WORKQUEUES_DEFAULT OFF)
 else()
   set(ENABLE_INTERNAL_PTHREAD_WORKQUEUES_DEFAULT ON)
@@ -172,7 +172,7 @@ if(__BUILTIN_TRAP)
   set(HAVE_NORETURN_BUILTIN_TRAP 1)
 endif()
 
-if(NOT CMAKE_SYSTEM_NAME STREQUAL Android)
+if(NOT ANDROID)
   find_package(LibRT)
 endif()
 
@@ -227,12 +227,12 @@ if(HAVE_MACH)
 else()
   set(USE_MACH_SEM 0)
 endif()
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
   add_compile_definitions($<$<COMPILE_LANGUAGE:C,CXX>:USE_WIN32_SEM>)
 endif()
 check_library_exists(pthread sem_init "" USE_POSIX_SEM)
 # NOTE: android has not always provided a libpthread, but uses the pthreads API
-if(CMAKE_SYSTEM_NAME STREQUAL Android)
+if(ANDROID)
   set(USE_POSIX_SEM 1)
 endif()
 
@@ -262,11 +262,11 @@ if (HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME)
 endif()
 check_symbol_exists(__printflike "bsd/sys/cdefs.h" HAVE_PRINTFLIKE)
 
-if(CMAKE_SYSTEM_NAME STREQUAL Android)
+if(aNDROID)
   set(ENABLE_DTRACE_DEFAULT OFF)
 endif()
 
-if(CMAKE_SYSTEM_NAME STREQUAL FreeBSD)
+if(BSD)
   add_compile_definitions($<$<COMPILE_LANGUAGE:C,CXX>:_WITH_DPRINTF>)
 endif()
 
@@ -289,7 +289,7 @@ if(leaks_EXECUTABLE)
 endif()
 
 
-if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+if(APPLE)
   add_compile_options($<:$<COMPILE_LANGUAGE:C,CXX>:-fmodule-map-file=${PROJECT_SOURCE_DIR}/dispatch/darwin/module.modulemap>
                       $<:$<COMPILE_LANGUAGE:C,CXX>:-fmodule-map-file=${PROJECT_SOURCE_DIR}/private/darwin/module.modulemap>)
 else()
@@ -304,7 +304,7 @@ add_compile_definitions($<$<COMPILE_LANGUAGE:C,CXX>:HAVE_CONFIG_H>)
 
 if(ENABLE_SWIFT)
   if(NOT SWIFT_SYSTEM_NAME)
-    if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+    if(APPLE)
       set(SWIFT_SYSTEM_NAME macosx)
     else()
       set(SWIFT_SYSTEM_NAME "$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>")

cmake/modules/DispatchCompilerWarnings.cmake

@@ -69,7 +69,7 @@ else()
   add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Wno-void-pointer-to-int-cast>)
   add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Wno-vla>)
 
-  if(CMAKE_SYSTEM_NAME STREQUAL Android)
+  if(ANDROID)
     add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Wno-incompatible-function-pointer-types>)
     add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Wno-implicit-function-declaration>)
     add_compile_options($<$<COMPILE_LANGUAGE:C,CXX>:-Wno-conversion>)

cmake/modules/DispatchSanitization.cmake

@@ -2,7 +2,7 @@
 set(DISPATCH_USE_SANITIZER "" CACHE STRING
     "Define the sanitizer used to build binaries and tests.")
 
-if(CMAKE_SYSTEM_NAME STREQUAL Darwin AND DISPATCH_USE_SANITIZER)
+if(APPLE AND DISPATCH_USE_SANITIZER)
   message(FATAL_ERROR "building libdispatch with sanitization is not supported on Darwin")
 endif()
 

cmake/modules/SwiftSupport.cmake

@@ -10,7 +10,7 @@ function(get_swift_host_arch result_var_name)
   if("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
     set("${result_var_name}" "x86_64" PARENT_SCOPE)
   elseif ("${CMAKE_SYSTEM_PROCESSOR}" MATCHES "AArch64|aarch64|arm64|ARM64")
-    if(CMAKE_SYSTEM_NAME MATCHES Darwin)
+    if(APPLE)
       set("${result_var_name}" "arm64" PARENT_SCOPE)
     else()
       set("${result_var_name}" "aarch64" PARENT_SCOPE)
@@ -28,7 +28,7 @@ function(get_swift_host_arch result_var_name)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7l")
     set("${result_var_name}" "armv7" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" MATCHES "amd64|AMD64")
-    if(CMAKE_SYSTEM_NAME MATCHES "Windows")
+    if(WIN32)
       set("${result_var_name}" "x86_64" PARENT_SCOPE)
     else()
       set("${result_var_name}" "amd64" PARENT_SCOPE)

dispatch/CMakeLists.txt

@@ -1,5 +1,5 @@
 
-if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+if(APPLE)
   set(DISPATCH_MODULE_MAP ${PROJECT_SOURCE_DIR}/dispatch/darwin/module.modulemap)
 else()
   set(DISPATCH_MODULE_MAP ${PROJECT_SOURCE_DIR}/dispatch/generic/module.modulemap)

src/BlocksRuntime/CMakeLists.txt

@@ -2,7 +2,7 @@
 add_library(BlocksRuntime
   data.c
   runtime.c)
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
   target_sources(BlocksRuntime PRIVATE
     BlocksRuntime.def)
 

src/CMakeLists.txt

@@ -1,5 +1,5 @@
 
-if(NOT CMAKE_SYSTEM_NAME STREQUAL Darwin)
+if(NOT APPLE)
   add_subdirectory(BlocksRuntime)
 endif()
 
@@ -57,7 +57,7 @@ add_library(dispatch
   shims/yield.c
   shims/yield.h)
 
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
   target_sources(dispatch PRIVATE
     shims/generic_sys_queue.h
     shims/generic_win_stubs.c
@@ -96,11 +96,11 @@ target_include_directories(dispatch PUBLIC
 target_include_directories(dispatch PRIVATE
   ${PROJECT_SOURCE_DIR}/private)
 
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
   target_compile_definitions(dispatch PRIVATE
     _CRT_NONSTDC_NO_WARNINGS
     _CRT_SECURE_NO_WARNINGS)
-elseif(CMAKE_SYSTEM_NAME STREQUAL Android)
+elseif(ANDROID)
   target_compile_options(dispatch PRIVATE
     -U_GNU_SOURCE)
 endif()
@@ -150,7 +150,7 @@ target_link_libraries(dispatch PRIVATE
   Threads::Threads)
 target_link_libraries(dispatch PUBLIC
   BlocksRuntime::BlocksRuntime)
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
   target_link_libraries(dispatch PRIVATE
     AdvAPI32
     ShLwApi
@@ -159,15 +159,15 @@ if(CMAKE_SYSTEM_NAME STREQUAL Windows)
     synchronization)
 endif()
 
-if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+if(APPLE)
   set_property(TARGET dispatch APPEND_STRING PROPERTY LINK_FLAGS
     "-Xlinker -compatibility_version -Xlinker 1"
     "-Xlinker -current_version -Xlinker ${VERSION}"
     "-Xlinker -dead_strip"
     "-Xlinker -alias_list -Xlinker ${PROJECT_SOURCE_DIR}/xcodeconfig/libdispatch.aliases")
 endif()
 
-if(NOT CMAKE_SYSTEM_NAME MATCHES "Darwin|Windows")
+if(NOT APPLE AND NOT WIN32)
   set_target_properties(dispatch PROPERTIES INSTALL_RPATH "$ORIGIN")
 endif()
 

src/swift/CMakeLists.txt

@@ -31,7 +31,7 @@ target_link_libraries(swiftDispatch PRIVATE
   BlocksRuntime::BlocksRuntime)
 target_link_libraries(swiftDispatch PUBLIC
   dispatch)
-if(NOT CMAKE_SYSTEM_NAME MATCHES "Darwin|Windows")
+if(NOT APPLE AND NOT WIN32)
   target_link_options(swiftDispatch PRIVATE "SHELL:-no-toolchain-stdlib-rpath")
   set_target_properties(swiftDispatch PROPERTIES INSTALL_RPATH "$ORIGIN")
 endif()

tests/CMakeLists.txt

@@ -1,5 +1,5 @@
 
-if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+if(WIN32)
     execute_process(COMMAND
                       "${CMAKE_COMMAND}" -E copy_directory "${PROJECT_SOURCE_DIR}/private"
                       "${CMAKE_CURRENT_BINARY_DIR}/dispatch")
@@ -15,7 +15,7 @@ else()
                       "${CMAKE_CURRENT_BINARY_DIR}/leaks-wrapper")
 endif()
 
-if(CMAKE_SYSTEM_NAME STREQUAL Linux)
+if(LINUX)
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lrt")
 endif()
 
@@ -92,8 +92,7 @@ function(add_unit_test name)
   # fails with the multiple definition errors seen in android/ndk#176, so I
   # pulled in this workaround noted there. The tests build and run with this
   # flag applied.
-  if(NOT BUILD_SHARED_LIBS AND CMAKE_SYSTEM_NAME STREQUAL Android AND
-     CMAKE_SYSTEM_PROCESSOR STREQUAL armv7-a)
+  if(NOT BUILD_SHARED_LIBS AND ANDROID AND CMAKE_SYSTEM_PROCESSOR STREQUAL armv7-a)
     target_link_options(${name} PRIVATE "LINKER:--allow-multiple-definition")
   endif()
   target_link_libraries(${name}
@@ -162,7 +161,7 @@ if(EXTENDED_TEST_SUITE)
 endif()
 
 # add C tests for platform-specific functionality when applicable
-if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+if(APPLE)
   list(APPEND DISPATCH_C_TESTS
        deadname
        proc