Rollback of commit 50adddf01b8d7f46fba6bee12ebbb41c31c87165.

*** Reason for rollback ***

Makes some tests fail, oddly enough.

*** Original change description ***

Fixes to use dylib on MacOS X.

The change in LinkCommandLine.java fixes the error "ld: library not found for -ltbb.dylib". The change in osx_gcc_wrapper.sh fixes the error "dyld: Library not loaded: @rpath/libtbb.dylib".

See https://groups.google.com/forum/#!topic/bazel-discuss/bs8BnXYRjzY

--
MOS_MIGRATED_REVID=101012689
diff --git a/tools/cpp/osx_gcc_wrapper.sh b/tools/cpp/osx_gcc_wrapper.sh
index d41854a..a8eb46a 100755
--- a/tools/cpp/osx_gcc_wrapper.sh
+++ b/tools/cpp/osx_gcc_wrapper.sh
@@ -58,8 +58,8 @@
 
 function get_library_path() {
     for libdir in ${LIB_DIRS}; do
-        if [ -f ${libdir}/lib$1.dylib ]; then
-            echo "${libdir}/lib$1.dylib"
+        if [ -f ${libdir}/lib$1.so ]; then
+            echo "${libdir}/lib$1.so"
         fi
     done
 }
@@ -87,7 +87,7 @@
     for lib in ${LIBS}; do
         libpath=$(get_library_path ${lib})
         if [ -n "${libpath}" ]; then
-            ${INSTALL_NAME_TOOL} -change "@rpath/lib${lib}.dylib" $(get_otool_path "${libpath}") "${OUTPUT}"
+            ${INSTALL_NAME_TOOL} -change $(get_otool_path "${libpath}") "@loader_path/${RPATH}/lib${lib}.so" "${OUTPUT}"
         fi
     done
 fi