diff --git a/configure.ac b/configure.ac
index 1caa9be5c4..02eebf6924 100644
--- a/configure.ac
+++ b/configure.ac
@@ -250,6 +250,19 @@ AC_SUBST(bzip2_bin)
 AC_SUBST(bzip2_bin_test)
 
 
+# Whether to use the Boehm garbage collector.
+AC_ARG_WITH(boehm-gc, AC_HELP_STRING([--with-boehm-gc=PATH],
+  [prefix of the Boehm GC package to enable garbage collection in the Nix expression evaluator]),
+  boehmgc=$withval, boehmgc=)
+if test -n "$boehmgc"; then
+  boehmgc_lib="-L$boehmgc/lib -lgc"
+  CXXFLAGS="-I$boehmgc/include $CXXFLAGS"
+  AC_DEFINE(HAVE_BOEHMGC, 1, [Whether to use the Boehm garbage collector.])
+fi
+AC_SUBST(boehmgc_lib)
+AC_SUBST(boehmgc_include)
+  
+
 AC_ARG_ENABLE(init-state, AC_HELP_STRING([--disable-init-state],
   [do not initialise DB etc. in `make install']),
   init_state=$enableval, init_state=yes)
diff --git a/src/libexpr/Makefile.am b/src/libexpr/Makefile.am
index 24aa2968b1..e7228e1835 100644
--- a/src/libexpr/Makefile.am
+++ b/src/libexpr/Makefile.am
@@ -20,8 +20,7 @@ EXTRA_DIST = lexer.l parser.y
 
 AM_CXXFLAGS = \
  -I$(srcdir)/.. \
- -I$(srcdir)/../libutil -I$(srcdir)/../libstore \
- -I/home/eelco/Dev/nix/boehmgc/include
+ -I$(srcdir)/../libutil -I$(srcdir)/../libstore
 
 
 # Parser generation.
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 46978f6d0b..c8a031ac6d 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -8,9 +8,18 @@
 
 #include <cstring>
 
+#if HAVE_BOEHMGC
+
 #include <gc/gc.h>
 #include <gc/gc_cpp.h>
 
+#else
+
+#define GC_STRDUP strdup
+#define GC_MALLOC malloc
+
+#endif
+
 
 #define LocalNoInline(f) static f __attribute__((noinline)); f
 #define LocalNoInlineNoReturn(f) static f __attribute__((noinline, noreturn)); f
@@ -151,7 +160,7 @@ void EvalState::addPrimOp(const string & name,
     v.type = tPrimOp;
     v.primOp.arity = arity;
     v.primOp.fun = primOp;
-    v.primOp.name = GC_strdup(name2.c_str());
+    v.primOp.name = GC_STRDUP(name2.c_str());
     staticBaseEnv.vars[symbols.create(name)] = baseEnvDispl;
     baseEnv.values[baseEnvDispl++] = v;
     (*baseEnv.values[0].attrs)[symbols.create(name2)].value = v;
@@ -222,7 +231,7 @@ LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2,
 void mkString(Value & v, const char * s)
 {
     v.type = tString;
-    v.string.s = GC_strdup(s);
+    v.string.s = GC_STRDUP(s);
     v.string.context = 0;
 }
 
@@ -233,9 +242,9 @@ void mkString(Value & v, const string & s, const PathSet & context)
     if (!context.empty()) {
         unsigned int n = 0;
         v.string.context = (const char * *)
-            GC_malloc((context.size() + 1) * sizeof(char *));
+            GC_MALLOC((context.size() + 1) * sizeof(char *));
         foreach (PathSet::const_iterator, i, context) 
-            v.string.context[n++] = GC_strdup(i->c_str());
+            v.string.context[n++] = GC_STRDUP(i->c_str());
         v.string.context[n] = 0;
     }
 }
@@ -244,7 +253,7 @@ void mkString(Value & v, const string & s, const PathSet & context)
 void mkPath(Value & v, const char * s)
 {
     v.type = tPath;
-    v.path = GC_strdup(s);
+    v.path = GC_STRDUP(s);
 }
 
 
@@ -294,7 +303,11 @@ void EvalState::mkList(Value & v, unsigned int length)
 void EvalState::mkAttrs(Value & v)
 {
     v.type = tAttrs;
+#if HAVE_BOEHMGC
     v.attrs = new (UseGC) Bindings;
+#else
+    v.attrs = new Bindings;
+#endif
     nrAttrsets++;
 }
 
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 9144d99a4b..738ca9439f 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -7,7 +7,9 @@
 
 #include <map>
 
+#if HAVE_BOEHMGC
 #include <gc/gc_allocator.h>
+#endif
 
 
 namespace nix {
@@ -18,7 +20,11 @@ struct Env;
 struct Value;
 struct Attr;
 
+#if HAVE_BOEHMGC
 typedef std::map<Symbol, Attr, std::less<Symbol>, gc_allocator<std::pair<const Symbol, Attr> > > Bindings;
+#else
+typedef std::map<Symbol, Attr> Bindings;
+#endif
 
 
 typedef enum {
diff --git a/src/nix-env/Makefile.am b/src/nix-env/Makefile.am
index 169c85fcb6..a876b3eb38 100644
--- a/src/nix-env/Makefile.am
+++ b/src/nix-env/Makefile.am
@@ -5,7 +5,7 @@ nix_env_SOURCES = nix-env.cc profiles.cc profiles.hh user-env.cc user-env.hh hel
 nix_env_LDADD = ../libmain/libmain.la ../libexpr/libexpr.la \
  ../libstore/libstore.la ../libutil/libutil.la \
  ../boost/format/libformat.la @ADDITIONAL_NETWORK_LIBS@ \
- -L/home/eelco/Dev/nix/boehmgc/lib -lgc
+ @boehmgc_lib@
 
 nix-env.o: help.txt.hh
 
@@ -15,5 +15,4 @@ nix-env.o: help.txt.hh
 AM_CXXFLAGS = \
  -I$(srcdir)/.. \
  -I$(srcdir)/../libutil -I$(srcdir)/../libstore \
- -I$(srcdir)/../libexpr -I$(srcdir)/../libmain -I../libexpr \
- -I/home/eelco/Dev/nix/boehmgc/include
+ -I$(srcdir)/../libexpr -I$(srcdir)/../libmain -I../libexpr
diff --git a/src/nix-instantiate/Makefile.am b/src/nix-instantiate/Makefile.am
index c6455b116d..bc9792818c 100644
--- a/src/nix-instantiate/Makefile.am
+++ b/src/nix-instantiate/Makefile.am
@@ -4,7 +4,7 @@ nix_instantiate_SOURCES = nix-instantiate.cc help.txt
 nix_instantiate_LDADD = ../libmain/libmain.la ../libexpr/libexpr.la \
  ../libstore/libstore.la ../libutil/libutil.la \
  ../boost/format/libformat.la @ADDITIONAL_NETWORK_LIBS@ \
- -L/home/eelco/Dev/nix/boehmgc/lib -lgc
+ @boehmgc_lib@
 
 nix-instantiate.o: help.txt.hh
 
@@ -13,6 +13,4 @@ nix-instantiate.o: help.txt.hh
 
 AM_CXXFLAGS = \
  -I$(srcdir)/.. -I$(srcdir)/../libutil -I$(srcdir)/../libstore \
- -I$(srcdir)/../libexpr -I$(srcdir)/../libmain -I../libexpr \
- -I/home/eelco/Dev/nix/boehmgc/include
-
+ -I$(srcdir)/../libexpr -I$(srcdir)/../libmain -I../libexpr