boost: disable system Python.framework detection

There doesn't seem to be a --without-python flag and since the system
framework is always available the build tries to enable python support
while we have it disabled by default and explicitly don't pass in the
python headers.

pkgs/development/libraries/boost/darwin-no-system-python.patch

@@ -0,0 +1,45 @@
+diff --git a/tools/build/src/tools/python.jam b/tools/build/src/tools/python.jam
+index 273b28a..2d2031e 100644
+--- a/tools/build/src/tools/python.jam
++++ b/tools/build/src/tools/python.jam
+@@ -428,13 +428,7 @@ local rule windows-installed-pythons ( version ? )
+ 
+ local rule darwin-installed-pythons ( version ? )
+ {
+-    version ?= $(.version-countdown) ;
+-
+-    local prefix
+-      = [ GLOB /System/Library/Frameworks /Library/Frameworks
+-          : Python.framework ] ;
+-
+-    return $(prefix)/Versions/$(version)/bin/python ;
++    return ;
+ }
+ 
+ 
+@@ -890,25 +884,6 @@ local rule configure ( version ? : cmd-or-prefix ? : includes * : libraries ? :
+ 
+     # See if we can find a framework directory on darwin.
+     local framework-directory ;
+-    if $(target-os) = darwin
+-    {
+-        # Search upward for the framework directory.
+-        local framework-directory = $(libraries[-1]) ;
+-        while $(framework-directory:D=) && $(framework-directory:D=) != Python.framework
+-        {
+-            framework-directory = $(framework-directory:D) ;
+-        }
+-
+-        if $(framework-directory:D=) = Python.framework
+-        {
+-            debug-message framework directory is \"$(framework-directory)\" ;
+-        }
+-        else
+-        {
+-            debug-message "no framework directory found; using library path" ;
+-            framework-directory = ;
+-        }
+-    }
+ 
+     local dll-path = $(libraries) ;
+ 

pkgs/development/libraries/boost/generic.nix

@@ -87,11 +87,13 @@ stdenv.mkDerivation {
   inherit src;
 
   patchFlags = optionalString (hostPlatform.libc == "msvcrt") "-p0";
-  patches = patches ++ optional (hostPlatform.libc == "msvcrt") (fetchurl {
-    url = "https://svn.boost.org/trac/boost/raw-attachment/tickaet/7262/"
-        + "boost-mingw.patch";
-    sha256 = "0s32kwll66k50w6r5np1y5g907b7lcpsjhfgr7rsw7q5syhzddyj";
-  });
+  patches = patches
+    ++ optional stdenv.isDarwin ./darwin-no-system-python.patch
+    ++ optional (hostPlatform.libc == "msvcrt") (fetchurl {
+      url = "https://svn.boost.org/trac/boost/raw-attachment/tickaet/7262/"
+          + "boost-mingw.patch";
+      sha256 = "0s32kwll66k50w6r5np1y5g907b7lcpsjhfgr7rsw7q5syhzddyj";
+    });
 
   meta = {
     homepage = http://boost.org/;