diff --git a/.gitignore b/.gitignore
index b41ea36..9a242ee 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 gc-7.2alpha4.tar.gz
 /bdwgc-7_2alpha5-20110107.tar.bz2
+/gc-7.2alpha6.tar.gz
diff --git a/gc.spec b/gc.spec
index 7cd4482..199c9fd 100644
--- a/gc.spec
+++ b/gc.spec
@@ -1,17 +1,15 @@
 
-%define pre alpha5
-%define snap 20110107
+%define pre alpha6
 
 Summary: A garbage collector for C and C++ 
 Name:    gc	
 Version: 7.2
-Release: 0.3.%{pre}.%{snap}%{?dist}
+Release: 0.4.%{pre}%{?dist}
 
 Group:   System Environment/Libraries
 License: BSD
 Url:     http://www.hpl.hp.com/personal/Hans_Boehm/gc/	
-#Source0: http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc-%{version}%{?pre}.tar.gz
-Source0: http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/bdwgc-7_2alpha5-%{snap}.tar.bz2
+Source0: http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc-%{version}%{?pre}.tar.gz
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 ## upstreamable patches
@@ -33,8 +31,7 @@ used as a garbage collecting replacement for C malloc or C++ new.
 %package devel
 Summary: Libraries and header files for %{name} development 
 Group:   Development/Libraries
-Requires: %{name} = %{version}-%{release}
-Requires: pkgconfig
+Requires: %{name}%{?_isa} = %{version}-%{release}
 Obsoletes: libgc-devel < %{version}-%{release}
 Provides:  libgc-devel = %{version}-%{release}
 %description devel
@@ -53,11 +50,9 @@ that involves minimum overhead across a variety of architectures.
 
 
 %prep
-#setup -q -n gc-%{version}%{?pre}
-%setup -q -n bdwgc
+%setup -q -n gc-%{version}%{?pre}
 
 %patch50 -p1 -b .dup_cpp_headers
-
 # refresh auto*/libtool to purge rpaths
 rm -f libtool libtool.m4
 autoreconf -i -f
@@ -65,6 +60,9 @@ autoreconf -i -f
 
 %build
 
+# see bugzilla.redhat.com/689877
+CPPFLAGS="-DUSE_GET_STACKBASE_FOR_MAIN"; export CPPFLAGS
+
 %configure \
   --disable-dependency-tracking \
   --disable-static \
@@ -73,7 +71,6 @@ autoreconf -i -f
 %ifarch %{ix86}
   --enable-parallel-mark \
 %endif
-  --enable-threads=posix \
   --with-libatomic-ops=no
 
 make %{?_smp_mflags}
@@ -142,6 +139,10 @@ rm -rf %{buildroot}
 
 
 %changelog
+* Mon Jun 20 2011 Rex Dieter <rdieter@fedoraproject.rog> 7.2-0.4.alpha6.20110107
+- gc-7.2alpha6
+- build with -DUSE_GET_STACKBASE_FOR_MAIN (#689877)
+
 * Wed Feb 09 2011 Rex Dieter <rdieter@fedoraproject.org> 7.2-0.3.alpha5.20110107
 - bdwgc-7.2alpha4 20110107 snapshot
 
diff --git a/sources b/sources
index b99aac7..f378db9 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-4f3c130fc71ff23584edaa19a37739ee  bdwgc-7_2alpha5-20110107.tar.bz2
+319d0b18cc4eb735c8038ece9df055e4  gc-7.2alpha6.tar.gz