From a9d32dffb9397ce98806176f759fea4e77acf076 Mon Sep 17 00:00:00 2001
From: David Gobbi <david.gobbi@gmail.com>
Date: Mon, 14 Sep 2015 22:48:49 -0600
Subject: [PATCH] FindPythonLibs: Match include dir to library version

This commit ensures that FindPythonLibs has found the library before
before the search for the include dir begins.  The library prefix and
version can then be used to find the matching include dir.
---
 Modules/FindPythonLibs.cmake | 55 +++++++++++++++++++++++-------------
 1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/Modules/FindPythonLibs.cmake b/Modules/FindPythonLibs.cmake
index 1c8776bac3..1220860807 100644
--- a/Modules/FindPythonLibs.cmake
+++ b/Modules/FindPythonLibs.cmake
@@ -150,26 +150,41 @@ foreach(_CURRENT_VERSION ${_Python_VERSIONS})
     PATH_SUFFIXES python${_CURRENT_VERSION}/config
   )
 
-  set(PYTHON_FRAMEWORK_INCLUDES)
-  if(Python_FRAMEWORKS AND NOT PYTHON_INCLUDE_DIR)
-    foreach(dir ${Python_FRAMEWORKS})
-      list(APPEND PYTHON_FRAMEWORK_INCLUDES
-           ${dir}/Versions/${_CURRENT_VERSION}/include)
-    endforeach()
-  endif()
+  # Don't search for include dir until library location is known
+  if(PYTHON_LIBRARY)
 
-  find_path(PYTHON_INCLUDE_DIR
-    NAMES Python.h
-    PATHS
-      ${PYTHON_FRAMEWORK_INCLUDES}
-      [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\${_CURRENT_VERSION}\\InstallPath]/include
-      [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\${_CURRENT_VERSION}\\InstallPath]/include
-    PATH_SUFFIXES
-      python${_CURRENT_VERSION}mu
-      python${_CURRENT_VERSION}m
-      python${_CURRENT_VERSION}u
-      python${_CURRENT_VERSION}
-  )
+    # Use the library's install prefix as a hint
+    set(_Python_INCLUDE_PATH_HINT)
+    get_filename_component(_PREFIX ${PYTHON_LIBRARY} PATH)
+    get_filename_component(_PREFIX ${_PREFIX} PATH)
+    if(_PREFIX)
+      set(_Python_INCLUDE_PATH_HINT ${_PREFIX}/include)
+    endif()
+
+    # Add framework directories to the search paths
+    set(PYTHON_FRAMEWORK_INCLUDES)
+    if(Python_FRAMEWORKS AND NOT PYTHON_INCLUDE_DIR)
+      foreach(dir ${Python_FRAMEWORKS})
+        list(APPEND PYTHON_FRAMEWORK_INCLUDES
+          ${dir}/Versions/${_CURRENT_VERSION}/include)
+      endforeach()
+    endif()
+
+    find_path(PYTHON_INCLUDE_DIR
+      NAMES Python.h
+      HINTS
+        ${_Python_INCLUDE_PATH_HINT}
+      PATHS
+        ${PYTHON_FRAMEWORK_INCLUDES}
+        [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\${_CURRENT_VERSION}\\InstallPath]/include
+        [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\${_CURRENT_VERSION}\\InstallPath]/include
+      PATH_SUFFIXES
+        python${_CURRENT_VERSION}mu
+        python${_CURRENT_VERSION}m
+        python${_CURRENT_VERSION}u
+        python${_CURRENT_VERSION}
+    )
+  endif()
 
   # For backward compatibility, set PYTHON_INCLUDE_PATH.
   set(PYTHON_INCLUDE_PATH "${PYTHON_INCLUDE_DIR}")
@@ -187,6 +202,8 @@ foreach(_CURRENT_VERSION ${_Python_VERSIONS})
   endif()
 endforeach()
 
+unset(_Python_INCLUDE_PATH_HINT)
+
 mark_as_advanced(
   PYTHON_DEBUG_LIBRARY
   PYTHON_LIBRARY