Make sleef compilable if CMAKE_OSX_ARCHITECTURES is passed (#376)

* Simplify x86 arch check

* Fix sleef compilation when CMAKE_OSX_ARCHITECTURES is passed

Test plan:
  Run `cmake .. -DCMAKE_OSX_ARCHITECTURES=x86_64 -G Ninja; ninja` on M1 Mac
  Run `cmake .. -DCMAKE_OSX_ARCHITECTURES=arm64 -G Ninja; ninja` on x86 Mac

* Compile host executable as universable binaries on OS X
If multiarch option is passed

CMakeLists.txt

@@ -206,6 +206,11 @@ set(TARGET_LIBARRAYMAP_OBJ "arraymap")
 function(add_host_executable TARGETNAME)
   if (NOT CMAKE_CROSSCOMPILING)
     add_executable(${TARGETNAME} ${ARGN})
+    # Ensure that Darwin host executable is built as universal binary
+    if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_ARCHITECTURES MATCHES "^(x86_64|arm64)$")
+      target_compile_options(${TARGETNAME} PRIVATE -arch "${CMAKE_HOST_SYSTEM_PROCESSOR}")
+      target_link_options(${TARGETNAME} PRIVATE -arch "${CMAKE_HOST_SYSTEM_PROCESSOR}")
+    endif()
   else()
     add_executable(${TARGETNAME} IMPORTED)
     set_property(TARGET ${TARGETNAME} PROPERTY IMPORTED_LOCATION ${NATIVE_BUILD_DIR}/bin/${TARGETNAME})
@@ -230,7 +235,11 @@ add_subdirectory("src")
 if(SLEEF_SHOW_CONFIG)
   message(STATUS "Configuring build for ${PROJECT_NAME}-v${SLEEF_VERSION}")
   message("   Target system: ${CMAKE_SYSTEM}")
-  message("   Target processor: ${CMAKE_SYSTEM_PROCESSOR}")
+  if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_ARCHITECTURES MATCHES "^(x86_64|arm64)$")
+    message("   Target processor: ${CMAKE_OSX_ARCHITECTURES}")
+  else()
+    message("   Target processor: ${CMAKE_SYSTEM_PROCESSOR}")
+  endif()
   message("   Host system: ${CMAKE_HOST_SYSTEM}")
   message("   Host processor: ${CMAKE_HOST_SYSTEM_PROCESSOR}")
   message("   Detected C compiler: ${CMAKE_C_COMPILER_ID} @ ${CMAKE_C_COMPILER}")

Configure.cmake

@@ -76,18 +76,24 @@ if(NOT CMAKE_BUILD_TYPE)
     "Debug" "Release" "RelWithDebInfo" "MinSizeRel")
 endif()
 
+# TARGET PROCESSOR DETECTION
+set(SLEEF_TARGET_PROCESSOR "${CMAKE_SYSTEM_PROCESSOR}")
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_ARCHITECTURES MATCHES "^(x86_64|arm64)$")
+  set(SLEEF_TARGET_PROCESSOR "${CMAKE_OSX_ARCHITECTURES}")
+endif()
+
 # PLATFORM DETECTION
 if(CMAKE_SIZEOF_VOID_P EQUAL 4)
   set(SLEEF_ARCH_32BIT ON CACHE INTERNAL "True for 32-bit architecture.")
 endif()
 
-if((CMAKE_SYSTEM_PROCESSOR MATCHES "x86") OR (CMAKE_SYSTEM_PROCESSOR MATCHES "AMD64") OR (CMAKE_SYSTEM_PROCESSOR MATCHES "amd64") OR (CMAKE_SYSTEM_PROCESSOR MATCHES "^i.86$"))
+if(SLEEF_TARGET_PROCESSOR MATCHES "(x86|AMD64|amd64|^i.86$)")
   set(SLEEF_ARCH_X86 ON CACHE INTERNAL "True for x86 architecture.")
 
   set(CLANG_FLAGS_ENABLE_PURECFMA_SCALAR "-mavx2;-mfma;-fno-strict-aliasing")
   set(CLANG_FLAGS_ENABLE_PUREC_SCALAR "-fno-strict-aliasing")
 
-elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64|arm64")
+elseif(SLEEF_TARGET_PROCESSOR MATCHES "aarch64|arm64")
   set(SLEEF_ARCH_AARCH64 ON CACHE INTERNAL "True for Aarch64 architecture.")
   # Aarch64 requires support for advsimdfma4
   set(COMPILER_SUPPORTS_ADVSIMD 1)