[Boost-build] OS X: use of DYLD_FALLBACK_LIBRARY_PATH

Subject: [Boost-build] OS X: use of DYLD_FALLBACK_LIBRARY_PATH
From: Jeroen van der Wulp (J.v.d.Wulp_at_[hidden])
Date: 2008-10-29 07:10:28

Hello Everyone,

Using the run rule in testing.jam sets the DYLD_LIBRARY_PATH environment 
variable before running an executable. This usually works, but recently
we found a case where this actually causes conflicts between libraries 
OS X framework and standard open source libraries installed for example 
through MacPorts.

I believe that DYLD_LIBRARY_PATH doesn't do the correct thing in this 
case. When linking a library that links against a library of which the 
location is known, e.g. /opt/local/lib/libjpeg.62.dylib (occurs like 
this in otool output of the library linked against), then it discards 
the path information and starts looking into paths specified in 
DYLD_LIBRARY_PATH variable. In the case of libjpeg the framework library 
libJPEG will be found, which is incompatible (Symbol not found: 
__cg_jpeg_resync_to_restart).

Using the DYLD_FALLBACK_LIBRARY_PATH variable seems to solve the 
problem. The paths listed in this variable are consulted only if 
libraries cannot be found in another way (more akin to LD_LIBRARY_PATH 
on other Unix systems). I like to propose the attached patch.

Best,

Jeroen van der Wulp

Index: 3rd-party/boost/tools/build/v2/util/os.jam
===================================================================
--- 3rd-party/boost/tools/build/v2/util/os.jam	(revision 5032)
+++ 3rd-party/boost/tools/build/v2/util/os.jam	(working copy)
@@ -71,7 +71,7 @@
 
 .shared-library-path-variable-CYGWIN = PATH ;
 
-.shared-library-path-variable-MACOSX = DYLD_LIBRARY_PATH ;
+.shared-library-path-variable-MACOSX = DYLD_FALLBACK_LIBRARY_PATH ;
 
 .shared-library-path-variable-AIX = LIBPATH ;