merge(3p/immer): Subtree merge at 'ad3e3556d' as 'third_party/immer'

Change-Id: I9636a41ad44b4218293833fd3e9456d9b07c731b

third_party/immer/cmake/FindBoehmGC.cmake

@@ -0,0 +1,108 @@
+# - Try to find Boehm GC
+#   Once done, this will define
+#
+#   BOEHM_GC_FOUND - system has Boehm GC
+#   BOEHM_GC_INCLUDE_DIR - the Boehm GC include directories
+#   BOEHM_GC_LIBRARIES - link these to use Boehm GC
+# 
+#   Copyright (c) 2010-2015  Takashi Kato <ktakashi@ymail.com>
+# 
+#   Redistribution and use in source and binary forms, with or without
+#   modification, are permitted provided that the following conditions
+#   are met:
+# 
+#   1. Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+# 
+#   2. Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in the
+#      documentation and/or other materials provided with the distribution.
+# 
+#   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+#   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+#   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+#   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+#   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+#   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# 
+#  $Id: $
+# 
+
+# CMake module to find Boehm GC
+
+# use pkg-config if available
+FIND_PACKAGE(PkgConfig)
+PKG_CHECK_MODULES(PC_BDW_GC QUIET bdw-gc)
+
+# try newer one first in case of gc.h is overwritten.
+FIND_PATH(BOEHM_GC_INCLUDE_DIR gc/gc.h
+  HINTS ${PC_BDW_GC_INCLUDEDIR} ${PC_BDW_GC_INCLUDE_DIRS})
+
+IF (NOT BOEHM_GC_INCLUDE_DIR)
+  FIND_PATH(BOEHM_GC_INCLUDE_DIR gc.h
+    HINTS ${PC_BDW_GC_INCLUDEDIR} ${PC_BDW_GC_INCLUDE_DIRS})
+  IF (BOEHM_GC_INCLUDE_DIR)
+    SET(HAVE_GC_H TRUE)
+  ENDIF()
+ELSE()
+  SET(HAVE_GC_GC_H TRUE)
+ENDIF()
+
+# For FreeBSD we need to use gc-threaded
+IF (${CMAKE_SYSTEM_NAME} STREQUAL "FreeBSD")
+  # checks if 'gc' supports 'GC_get_parallel' and if it does
+  # then use it
+  INCLUDE(${CMAKE_ROOT}/Modules/CheckCSourceCompiles.cmake)
+  # not sure if this links properly...
+  FIND_LIBRARY(BOEHM_GC_LIBRARIES NAMES gc
+    HINTS ${PC_BDW_GC_LIBDIR} ${PC_BDW_GC_LIBRARY_DIRS})
+  MESSAGE(STATUS "GC library ${BOEHM_GC_LIBRARIES}")
+  SET(CMAKE_REQUIRED_LIBRARIES "gc")
+  SET(CMAKE_REQUIRED_DEFINITIONS "-DGC_THREADS")
+  SET(CMAKE_REQUIRED_INCLUDES "${BOEHM_GC_INCLUDE_DIR}")
+  SET(CMAKE_REQUIRED_FLAGS "-L${PC_BDW_GC_LIBRARY_DIRS}")
+  MESSAGE(STATUS "Boehm GC include dir: ${CMAKE_REQUIRED_INCLUDES}")
+  CHECK_C_SOURCE_RUNS(
+    "#include <gc.h>
+int main() {
+int i= GC_get_parallel();
+return 0;
+}
+" GC_GET_PARALLEL_WORKS)
+  IF (NOT GC_GET_PARALLEL_WORKS)
+    MESSAGE(STATUS "Try gc-threaded")
+
+    # bdw-gc-threaded is the proper name for FreeBSD pkg-config
+    PKG_CHECK_MODULES(PC_BDW_GC_THREADED bdw-gc-threaded)
+    FIND_LIBRARY(BOEHM_GC_THREADED_LIBRARIES NAMES gc-threaded
+      HINTS ${PC_BDW_GC_THREADED_LIBDIR} ${PC_BDW_GC_THREADED_THREADED_DIRS})
+
+    MESSAGE(STATUS "GC threaded library ${BOEHM_GC_THREADED_LIBRARIES}")
+    IF (BOEHM_GC_THREADED_LIBRARIES)
+      # OK just use it
+      SET(BOEHM_GC_LIBRARIES "${BOEHM_GC_THREADED_LIBRARIES}")
+    ENDIF()
+  ENDIF()
+ELSE()
+  FIND_LIBRARY(BOEHM_GC_LIBRARIES NAMES gc
+    HINTS ${PC_BDW_GC_LIBDIR} ${PC_BDW_GC_LIBRARY_DIRS})
+  # OpenSolaris uses bgc as Boehm GC runtime in its package manager.
+  # so try it
+  IF (NOT BOEHM_GC_LIBRARIES)
+    FIND_LIBRARY(BOEHM_GC_LIBRARIES NAMES bgc
+      HINTS ${PC_BDW_GC_LIBDIR} ${PC_BDW_GC_LIBRARY_DIRS})
+  ENDIF()
+ENDIF()
+
+MESSAGE(STATUS "Found GC library: ${BOEHM_GC_LIBRARIES}")
+
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Boehm_GC DEFAULT_MSG
+                                  BOEHM_GC_LIBRARIES BOEHM_GC_INCLUDE_DIR)
+
+MARK_AS_ADVANCED(BOEHM_GC_LIBRARIES BOEHM_GC_INCLUDE_DIR)