summaryrefslogtreecommitdiff
path: root/Modules/Platform/Darwin.cmake
blob: 72844b53158c042c73a3a29b2f7a72c5c11f785b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
set(APPLE 1)

# Darwin versions:
#   6.x == Mac OSX 10.2 (Jaguar)
#   7.x == Mac OSX 10.3 (Panther)
#   8.x == Mac OSX 10.4 (Tiger)
#   9.x == Mac OSX 10.5 (Leopard)
#  10.x == Mac OSX 10.6 (Snow Leopard)
#  11.x == Mac OSX 10.7 (Lion)
#  12.x == Mac OSX 10.8 (Mountain Lion)
string(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\1" DARWIN_MAJOR_VERSION "${CMAKE_SYSTEM_VERSION}")
string(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\2" DARWIN_MINOR_VERSION "${CMAKE_SYSTEM_VERSION}")

# Do not use the "-Wl,-search_paths_first" flag with the OSX 10.2 compiler.
# Done this way because it is too early to do a TRY_COMPILE.
if(NOT DEFINED HAVE_FLAG_SEARCH_PATHS_FIRST)
  set(HAVE_FLAG_SEARCH_PATHS_FIRST 0)
  if("${DARWIN_MAJOR_VERSION}" GREATER 6)
    set(HAVE_FLAG_SEARCH_PATHS_FIRST 1)
  endif()
endif()
# More desirable, but does not work:
  #include(CheckCXXCompilerFlag)
  #CHECK_CXX_COMPILER_FLAG("-Wl,-search_paths_first" HAVE_FLAG_SEARCH_PATHS_FIRST)

set(CMAKE_SHARED_LIBRARY_PREFIX "lib")
set(CMAKE_SHARED_LIBRARY_SUFFIX ".dylib")
set(CMAKE_SHARED_MODULE_PREFIX "lib")
set(CMAKE_SHARED_MODULE_SUFFIX ".so")
set(CMAKE_MODULE_EXISTS 1)
set(CMAKE_DL_LIBS "")

# Enable rpath support for 10.5 and greater where it is known to work.
if("${DARWIN_MAJOR_VERSION}" GREATER 8)
  set(CMAKE_SHARED_LIBRARY_RUNTIME_C_FLAG "-Wl,-rpath,")
endif()

set(CMAKE_C_OSX_COMPATIBILITY_VERSION_FLAG "-compatibility_version ")
set(CMAKE_C_OSX_CURRENT_VERSION_FLAG "-current_version ")
set(CMAKE_CXX_OSX_COMPATIBILITY_VERSION_FLAG "${CMAKE_C_OSX_COMPATIBILITY_VERSION_FLAG}")
set(CMAKE_CXX_OSX_CURRENT_VERSION_FLAG "${CMAKE_C_OSX_CURRENT_VERSION_FLAG}")

set(CMAKE_C_LINK_FLAGS "-Wl,-headerpad_max_install_names")
set(CMAKE_CXX_LINK_FLAGS "-Wl,-headerpad_max_install_names")

if(HAVE_FLAG_SEARCH_PATHS_FIRST)
  set(CMAKE_C_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_C_LINK_FLAGS}")
  set(CMAKE_CXX_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_CXX_LINK_FLAGS}")
endif()

set(CMAKE_PLATFORM_HAS_INSTALLNAME 1)
set(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
set(CMAKE_SHARED_MODULE_CREATE_C_FLAGS "-bundle -Wl,-headerpad_max_install_names")
set(CMAKE_SHARED_MODULE_LOADER_C_FLAG "-Wl,-bundle_loader,")
set(CMAKE_SHARED_MODULE_LOADER_CXX_FLAG "-Wl,-bundle_loader,")
set(CMAKE_FIND_LIBRARY_SUFFIXES ".dylib" ".so" ".a")

# hack: if a new cmake (which uses CMAKE_INSTALL_NAME_TOOL) runs on an old build tree
# (where install_name_tool was hardcoded) and where CMAKE_INSTALL_NAME_TOOL isn't in the cache
# and still cmake didn't fail in CMakeFindBinUtils.cmake (because it isn't rerun)
# hardcode CMAKE_INSTALL_NAME_TOOL here to install_name_tool, so it behaves as it did before, Alex
if(NOT DEFINED CMAKE_INSTALL_NAME_TOOL)
  find_program(CMAKE_INSTALL_NAME_TOOL install_name_tool)
  mark_as_advanced(CMAKE_INSTALL_NAME_TOOL)
endif()

# Ask xcode-select where to find /Developer or fall back to ancient location.
execute_process(COMMAND xcode-select -print-path
  OUTPUT_VARIABLE _stdout
  OUTPUT_STRIP_TRAILING_WHITESPACE
  ERROR_VARIABLE _stderr
  RESULT_VARIABLE _failed)
if(NOT _failed AND IS_DIRECTORY ${_stdout})
  set(OSX_DEVELOPER_ROOT ${_stdout})
elseif(IS_DIRECTORY "/Developer")
  set(OSX_DEVELOPER_ROOT "/Developer")
else()
  set(OSX_DEVELOPER_ROOT "")
endif()

execute_process(COMMAND sw_vers -productVersion
  OUTPUT_VARIABLE CURRENT_OSX_VERSION
  OUTPUT_STRIP_TRAILING_WHITESPACE)

# Save CMAKE_OSX_ARCHITECTURES from the environment.
set(CMAKE_OSX_ARCHITECTURES "$ENV{CMAKE_OSX_ARCHITECTURES}" CACHE STRING
  "Build architectures for OSX")

#----------------------------------------------------------------------------
# _CURRENT_OSX_VERSION - as a two-component string: 10.5, 10.6, ...
#
string(REGEX REPLACE "^([0-9]+\\.[0-9]+).*$" "\\1"
  _CURRENT_OSX_VERSION "${CURRENT_OSX_VERSION}")

#----------------------------------------------------------------------------
# CMAKE_OSX_DEPLOYMENT_TARGET

# Set cache variable - end user may change this during ccmake or cmake-gui configure.
if(_CURRENT_OSX_VERSION VERSION_GREATER 10.3)
  set(CMAKE_OSX_DEPLOYMENT_TARGET "$ENV{MACOSX_DEPLOYMENT_TARGET}" CACHE STRING
    "Minimum OS X version to target for deployment (at runtime); newer APIs weak linked. Set to empty string for default value.")
endif()

#----------------------------------------------------------------------------
# CMAKE_OSX_SYSROOT

if(CMAKE_OSX_SYSROOT)
  # Use the existing value without further computation to choose a default.
  set(_CMAKE_OSX_SYSROOT_DEFAULT "${CMAKE_OSX_SYSROOT}")
elseif(NOT "x$ENV{SDKROOT}" STREQUAL "x" AND
        (NOT "x$ENV{SDKROOT}" MATCHES "/" OR IS_DIRECTORY "$ENV{SDKROOT}"))
  # Use the value of SDKROOT from the environment.
  set(_CMAKE_OSX_SYSROOT_DEFAULT "$ENV{SDKROOT}")
elseif("${CMAKE_GENERATOR}" MATCHES Xcode
       OR CMAKE_OSX_DEPLOYMENT_TARGET
       OR CMAKE_OSX_ARCHITECTURES MATCHES "[^;]"
       OR NOT EXISTS "/usr/include/sys/types.h")
  # Find installed SDKs in either Xcode-4.3+ or pre-4.3 SDKs directory.
  set(_CMAKE_OSX_SDKS_DIR "")
  if(OSX_DEVELOPER_ROOT)
    foreach(d Platforms/MacOSX.platform/Developer/SDKs SDKs)
      file(GLOB _CMAKE_OSX_SDKS ${OSX_DEVELOPER_ROOT}/${d}/*)
      if(_CMAKE_OSX_SDKS)
        set(_CMAKE_OSX_SDKS_DIR ${OSX_DEVELOPER_ROOT}/${d})
        break()
      endif()
    endforeach()
  endif()

  if(_CMAKE_OSX_SDKS_DIR)
    # Select SDK for current OSX version accounting for the known
    # specially named SDKs.
    set(_CMAKE_OSX_SDKS_VER_SUFFIX_10.4 "u")
    set(_CMAKE_OSX_SDKS_VER_SUFFIX_10.3 ".9")
    if(CMAKE_OSX_DEPLOYMENT_TARGET)
      set(_CMAKE_OSX_SDKS_VER ${CMAKE_OSX_DEPLOYMENT_TARGET}${_CMAKE_OSX_SDKS_VER_SUFFIX_${CMAKE_OSX_DEPLOYMENT_TARGET}})
      set(_CMAKE_OSX_SYSROOT_CHECK "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
      if(IS_DIRECTORY "${_CMAKE_OSX_SYSROOT_CHECK}")
        set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SYSROOT_CHECK}")
      else()
        set(_CMAKE_OSX_SDKS_VER ${_CURRENT_OSX_VERSION}${_CMAKE_OSX_SDKS_VER_SUFFIX_${_CURRENT_OSX_VERSION}})
        set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
        message(WARNING
          "CMAKE_OSX_DEPLOYMENT_TARGET is '${CMAKE_OSX_DEPLOYMENT_TARGET}' "
          "but the matching SDK does not exist at:\n \"${_CMAKE_OSX_SYSROOT_CHECK}\"\n"
          "Instead using SDK:\n \"${_CMAKE_OSX_SYSROOT_DEFAULT}\"\n"
          "matching the host OS X version."
          )
      endif()
    else()
      set(_CMAKE_OSX_SDKS_VER ${_CURRENT_OSX_VERSION}${_CMAKE_OSX_SDKS_VER_SUFFIX_${_CURRENT_OSX_VERSION}})
      set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
    endif()
  else()
    # Assume developer files are in root (such as Xcode 4.5 command-line tools).
    set(_CMAKE_OSX_SYSROOT_DEFAULT "")
  endif()
endif()

# Set cache variable - end user may change this during ccmake or cmake-gui configure.
# Choose the type based on the current value.
set(_CMAKE_OSX_SYSROOT_TYPE STRING)
foreach(v CMAKE_OSX_SYSROOT _CMAKE_OSX_SYSROOT_DEFAULT)
  if("x${${v}}" MATCHES "/")
    set(_CMAKE_OSX_SYSROOT_TYPE PATH)
    break()
  endif()
endforeach()
set(CMAKE_OSX_SYSROOT "${_CMAKE_OSX_SYSROOT_DEFAULT}" CACHE ${_CMAKE_OSX_SYSROOT_TYPE}
  "The product will be built against the headers and libraries located inside the indicated SDK.")

# Transform the cached value to something we can use.
set(_CMAKE_OSX_SYSROOT_ORIG "${CMAKE_OSX_SYSROOT}")
set(_CMAKE_OSX_SYSROOT_PATH "")
if(CMAKE_OSX_SYSROOT)
  if("x${CMAKE_OSX_SYSROOT}" MATCHES "/")
    # This is a path to the SDK.  Make sure it exists.
    if(NOT IS_DIRECTORY "${CMAKE_OSX_SYSROOT}")
      message(WARNING "Ignoring CMAKE_OSX_SYSROOT value:\n ${CMAKE_OSX_SYSROOT}\n"
        "because the directory does not exist.")
      set(CMAKE_OSX_SYSROOT "")
      set(_CMAKE_OSX_SYSROOT_ORIG "")
    endif()
    set(_CMAKE_OSX_SYSROOT_PATH "${CMAKE_OSX_SYSROOT}")
  else()
    # Transform the sdk name into a path.
    execute_process(
      COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
      OUTPUT_VARIABLE _stdout
      OUTPUT_STRIP_TRAILING_WHITESPACE
      ERROR_VARIABLE _stderr
      RESULT_VARIABLE _failed
      )
    if(NOT _failed AND IS_DIRECTORY "${_stdout}")
      set(_CMAKE_OSX_SYSROOT_PATH "${_stdout}")
      # For non-Xcode generators use the path.
      if(NOT "${CMAKE_GENERATOR}" MATCHES "Xcode")
        set(CMAKE_OSX_SYSROOT "${_CMAKE_OSX_SYSROOT_PATH}")
      endif()
    endif()
  endif()
endif()

# Make sure the combination of SDK and Deployment Target are allowed
if(CMAKE_OSX_DEPLOYMENT_TARGET)
  if("${_CMAKE_OSX_SYSROOT_PATH}" MATCHES "^.*/MacOSX([0-9]+\\.[0-9]+)[^/]*\\.sdk")
    set(_sdk_ver "${CMAKE_MATCH_1}")
  elseif("${_CMAKE_OSX_SYSROOT_ORIG}" MATCHES "^macosx([0-9]+\\.[0-9]+)$")
    set(_sdk_ver "${CMAKE_MATCH_1}")
  else()
    message(FATAL_ERROR
      "CMAKE_OSX_DEPLOYMENT_TARGET is '${CMAKE_OSX_DEPLOYMENT_TARGET}' "
      "but CMAKE_OSX_SYSROOT:\n \"${_CMAKE_OSX_SYSROOT_ORIG}\"\n"
      "is not set to a MacOSX SDK with a recognized version.  "
      "Either set CMAKE_OSX_SYSROOT to a valid SDK or set "
      "CMAKE_OSX_DEPLOYMENT_TARGET to empty.")
  endif()
  if(CMAKE_OSX_DEPLOYMENT_TARGET VERSION_GREATER "${_sdk_ver}")
    message(FATAL_ERROR
      "CMAKE_OSX_DEPLOYMENT_TARGET (${CMAKE_OSX_DEPLOYMENT_TARGET}) "
      "is greater than CMAKE_OSX_SYSROOT SDK:\n ${_CMAKE_OSX_SYSROOT_ORIG}\n"
      "Please set CMAKE_OSX_DEPLOYMENT_TARGET to ${_sdk_ver} or lower.")
  endif()
endif()

if("${CMAKE_BACKWARDS_COMPATIBILITY}" MATCHES "^1\\.[0-6]$")
  set(CMAKE_SHARED_MODULE_CREATE_C_FLAGS
    "${CMAKE_SHARED_MODULE_CREATE_C_FLAGS} -flat_namespace -undefined suppress")
endif()

# Enable shared library versioning.
set(CMAKE_SHARED_LIBRARY_SONAME_C_FLAG "-install_name")

# Xcode does not support -isystem yet.
if(XCODE)
  set(CMAKE_INCLUDE_SYSTEM_FLAG_C)
  set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX)
endif()

if("${_CURRENT_OSX_VERSION}" VERSION_LESS "10.5")
  # Need to list dependent shared libraries on link line.  When building
  # with -isysroot (for universal binaries), the linker always looks for
  # dependent libraries under the sysroot.  Listing them on the link
  # line works around the problem.
  set(CMAKE_LINK_DEPENDENT_LIBRARY_FILES 1)
endif()

set(CMAKE_C_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
set(CMAKE_CXX_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
set(CMAKE_C_CREATE_SHARED_LIBRARY
  "<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> <SONAME_FLAG> <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
set(CMAKE_CXX_CREATE_SHARED_LIBRARY
  "<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> <SONAME_FLAG> <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
set(CMAKE_Fortran_CREATE_SHARED_LIBRARY
  "<CMAKE_Fortran_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_Fortran_FLAGS> <LINK_FLAGS> -o <TARGET> <SONAME_FLAG> <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")

set(CMAKE_CXX_CREATE_SHARED_MODULE
      "<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

set(CMAKE_C_CREATE_SHARED_MODULE
      "<CMAKE_C_COMPILER>  <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

set(CMAKE_Fortran_CREATE_SHARED_MODULE
      "<CMAKE_Fortran_COMPILER>  <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_Fortran_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

set(CMAKE_C_CREATE_MACOSX_FRAMEWORK
      "<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> <SONAME_FLAG> <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
set(CMAKE_CXX_CREATE_MACOSX_FRAMEWORK
      "<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> <SONAME_FLAG> <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")


# default to searching for frameworks first
if(NOT DEFINED CMAKE_FIND_FRAMEWORK)
  set(CMAKE_FIND_FRAMEWORK FIRST)
endif()

# Older OS X linkers do not report their framework search path
# with -v but "man ld" documents the following locations.
set(CMAKE_PLATFORM_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES
  ${_CMAKE_OSX_SYSROOT_PATH}/Library/Frameworks
  ${_CMAKE_OSX_SYSROOT_PATH}/System/Library/Frameworks
  )
if(_CMAKE_OSX_SYSROOT_PATH)
  # Treat some paths as implicit so we do not override the SDK versions.
  list(APPEND CMAKE_PLATFORM_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES
    /System/Library/Frameworks)
endif()
if("${_CURRENT_OSX_VERSION}" VERSION_LESS "10.5")
  # Older OS X tools had more implicit paths.
  list(APPEND CMAKE_PLATFORM_IMPLICIT_LINK_FRAMEWORK_DIRECTORIES
    ${_CMAKE_OSX_SYSROOT_PATH}/Network/Library/Frameworks)
endif()

# set up the default search directories for frameworks
set(CMAKE_SYSTEM_FRAMEWORK_PATH
  ~/Library/Frameworks
  )
if(_CMAKE_OSX_SYSROOT_PATH)
  list(APPEND CMAKE_SYSTEM_FRAMEWORK_PATH
    ${_CMAKE_OSX_SYSROOT_PATH}/Library/Frameworks
    ${_CMAKE_OSX_SYSROOT_PATH}/Network/Library/Frameworks
    ${_CMAKE_OSX_SYSROOT_PATH}/System/Library/Frameworks
    )
endif()
list(APPEND CMAKE_SYSTEM_FRAMEWORK_PATH
  /Library/Frameworks
  /Network/Library/Frameworks
  /System/Library/Frameworks)

# Warn about known system mis-configuration case.
if(CMAKE_OSX_SYSROOT)
  get_property(_IN_TC GLOBAL PROPERTY IN_TRY_COMPILE)
  if(NOT _IN_TC AND
     NOT IS_SYMLINK "${CMAKE_OSX_SYSROOT}/Library/Frameworks"
     AND IS_SYMLINK "${CMAKE_OSX_SYSROOT}/Library/Frameworks/Frameworks")
    message(WARNING "The SDK Library/Frameworks path\n"
      " ${CMAKE_OSX_SYSROOT}/Library/Frameworks\n"
      "is not set up correctly on this system.  "
      "This is known to occur when installing Xcode 3.2.6:\n"
      " http://bugs.python.org/issue14018\n"
      "The problem may cause build errors that report missing system frameworks.  "
      "Fix your SDK symlinks to resolve this issue and avoid this warning."
      )
  endif()
endif()

# default to searching for application bundles first
if(NOT DEFINED CMAKE_FIND_APPBUNDLE)
  set(CMAKE_FIND_APPBUNDLE FIRST)
endif()
# set up the default search directories for application bundles
set(_apps_paths)
foreach(_path
  "~/Applications"
  "/Applications"
  "${OSX_DEVELOPER_ROOT}/../Applications" # Xcode 4.3+
  "${OSX_DEVELOPER_ROOT}/Applications"    # pre-4.3
  )
  get_filename_component(_apps "${_path}" ABSOLUTE)
  if(EXISTS "${_apps}")
    list(APPEND _apps_paths "${_apps}")
  endif()
endforeach()
list(REMOVE_DUPLICATES _apps_paths)
set(CMAKE_SYSTEM_APPBUNDLE_PATH
  ${_apps_paths})
unset(_apps_paths)

include(Platform/UnixPaths)
if(_CMAKE_OSX_SYSROOT_PATH AND EXISTS ${_CMAKE_OSX_SYSROOT_PATH}/usr/include)
  list(APPEND CMAKE_SYSTEM_PREFIX_PATH ${_CMAKE_OSX_SYSROOT_PATH}/usr)
  foreach(lang C CXX)
    list(APPEND CMAKE_${lang}_IMPLICIT_INCLUDE_DIRECTORIES ${_CMAKE_OSX_SYSROOT_PATH}/usr/include)
  endforeach()
endif()
list(APPEND CMAKE_SYSTEM_PREFIX_PATH
  /sw        # Fink
  /opt/local # MacPorts
  )