add CMake script for finding hwy, copied from libjxl. Fixes #1084

PiperOrigin-RevId: 496353054

FindHWY.cmake

@@ -0,0 +1,66 @@
+# Copyright (c) the JPEG XL Project Authors. All rights reserved.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in https://github.com/libjxl/libjxl/blob/main/LICENSE.
+
+find_package(PkgConfig QUIET)
+if (PkgConfig_FOUND)
+  pkg_check_modules(PC_HWY QUIET libhwy)
+  set(HWY_VERSION ${PC_HWY_VERSION})
+endif ()
+
+find_path(HWY_INCLUDE_DIR
+  NAMES hwy/highway.h
+  HINTS ${PC_HWY_INCLUDEDIR} ${PC_HWY_INCLUDE_DIRS}
+)
+
+find_library(HWY_LIBRARY
+  NAMES ${HWY_NAMES} hwy
+  HINTS ${PC_HWY_LIBDIR} ${PC_HWY_LIBRARY_DIRS}
+)
+
+if (HWY_INCLUDE_DIR AND NOT HWY_VERSION)
+  if (EXISTS "${HWY_INCLUDE_DIR}/hwy/highway.h")
+    file(READ "${HWY_INCLUDE_DIR}/hwy/highway.h" HWY_VERSION_CONTENT)
+
+    string(REGEX MATCH "#define HWY_MAJOR +([0-9]+)" _dummy "${HWY_VERSION_CONTENT}")
+    set(HWY_VERSION_MAJOR "${CMAKE_MATCH_1}")
+
+    string(REGEX MATCH "#define +HWY_MINOR +([0-9]+)" _dummy "${HWY_VERSION_CONTENT}")
+    set(HWY_VERSION_MINOR "${CMAKE_MATCH_1}")
+
+    string(REGEX MATCH "#define +HWY_PATCH +([0-9]+)" _dummy "${HWY_VERSION_CONTENT}")
+    set(HWY_VERSION_PATCH "${CMAKE_MATCH_1}")
+
+    set(HWY_VERSION "${HWY_VERSION_MAJOR}.${HWY_VERSION_MINOR}.${HWY_VERSION_PATCH}")
+  endif ()
+endif ()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(HWY
+  FOUND_VAR HWY_FOUND
+  REQUIRED_VARS HWY_LIBRARY HWY_INCLUDE_DIR
+  VERSION_VAR HWY_VERSION
+)
+
+if (HWY_LIBRARY AND NOT TARGET hwy)
+  add_library(hwy INTERFACE IMPORTED GLOBAL)
+
+  if(CMAKE_VERSION VERSION_LESS "3.13.5")
+    set_property(TARGET hwy PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${HWY_INCLUDE_DIR})
+    target_link_libraries(hwy INTERFACE ${HWY_LIBRARY})
+    set_property(TARGET hwy PROPERTY INTERFACE_COMPILE_OPTIONS ${PC_HWY_CFLAGS_OTHER})
+  else()
+    target_include_directories(hwy INTERFACE ${HWY_INCLUDE_DIR})
+    target_link_libraries(hwy INTERFACE ${HWY_LIBRARY})
+    target_link_options(hwy INTERFACE ${PC_HWY_LDFLAGS_OTHER})
+    target_compile_options(hwy INTERFACE ${PC_HWY_CFLAGS_OTHER})
+  endif()
+endif()
+
+mark_as_advanced(HWY_INCLUDE_DIR HWY_LIBRARY)
+
+if (HWY_FOUND)
+    set(HWY_LIBRARIES ${HWY_LIBRARY})
+    set(HWY_INCLUDE_DIRS ${HWY_INCLUDE_DIR})
+endif ()