diff --git a/.hgignore b/.hgignore
index 51566e20..05828695 100644
--- a/.hgignore
+++ b/.hgignore
@@ -16,4 +16,4 @@ junk*
 gc
 gc6.8
 chibi-scheme
-
+include/chibi/install.h
diff --git a/Makefile b/Makefile
index 4214d381..7606ca9f 100644
--- a/Makefile
+++ b/Makefile
@@ -37,12 +37,13 @@ endif
 
 ifdef USE_BOEHM
 GCLDFLAGS := -lgc
+CPPFLAGS := $(CPPFLAGS) -Iinclude -DUSE_BOEHM=1
 else
 GCLDFLAGS :=
+CPPFLAGS := $(CPPFLAGS) -Iinclude
 endif
 
 LDFLAGS  := $(LDFLAGS) -lm
-CPPFLAGS := $(CPPFLAGS) -Iinclude
 CFLAGS   := $(CFLAGS) -Wall -O2 -g
 
 INCLUDES = include/chibi/sexp.h include/chibi/config.h include/chibi/install.h
@@ -60,10 +61,10 @@ main.o: main.c $(INCLUDES) Makefile
 	$(CC) -c $(CPPFLAGS) $(CFLAGS) -o $@ $<
 
 libchibi-scheme$(SO): eval.o sexp.o
-	$(CC) -dynamiclib -o $@ $^
+	$(CC) $(CLIBFLAGS) -o $@ $^ $(LDFLAGS) $(GCLDFLAGS)
 
 chibi-scheme$(EXE): main.o libchibi-scheme$(SO)
-	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< $(LDFLAGS) $(GCLDFLAGS) -L. -lchibi-scheme
+	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< -L. -lchibi-scheme
 
 chibi-scheme-static$(EXE): main.o eval.o sexp.o
 	$(CC) $(CFLAGS) $(STATICFLAGS) -o $@ $^ $(LDFLAGS) $(GCLDFLAGS)
diff --git a/gc.c b/gc.c
index 37444e04..7144cbee 100644
--- a/gc.c
+++ b/gc.c
@@ -154,7 +154,7 @@ sexp_heap sexp_make_heap (size_t size) {
   sexp free, next;
   sexp_heap h = (sexp_heap) malloc(sizeof(struct sexp_heap) + size);
   if (! h) {
-    fprintf(stderr, "out of memory allocating %ld byte heap, aborting\n", size);
+    fprintf(stderr, "out of memory allocating %lu byte heap, aborting\n", size);
     exit(70);
   }
   h->size = size;
@@ -222,7 +222,7 @@ void* sexp_alloc (sexp ctx, size_t size) {
       sexp_grow_heap(ctx, size);
     res = sexp_try_alloc(ctx, size);
     if (! res) {
-      fprintf(stderr, "out of memory allocating %ld bytes, aborting\n", size);
+      fprintf(stderr, "out of memory allocating %lu bytes, aborting\n", size);
       exit(70);
     }
   }
diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 348052d4..2bbc323c 100644
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -215,7 +215,7 @@ struct sexp_struct {
 #define sexp_gc_preserve(ctx, x, y)
 #define sexp_gc_release(ctx, x, y)
 
-#include "gc.h"
+#include "gc/gc.h"
 #define sexp_alloc(ctx, size)        GC_malloc(size)
 #define sexp_alloc_atomic(ctx, size) GC_malloc_atomic(size)
 #define sexp_realloc(ctx, x, size)   GC_realloc(x, size)
diff --git a/sexp.c b/sexp.c
index 775f64c8..bd1a851b 100644
--- a/sexp.c
+++ b/sexp.c
@@ -629,7 +629,7 @@ sexp sexp_make_input_string_port (sexp ctx, sexp str) {
 sexp sexp_make_output_string_port (sexp ctx) {
   FILE *out;
   sexp buf = sexp_alloc_type(ctx, string, SEXP_STRING), res;
-  out = open_memstream(&sexp_string_data(buf), &sexp_string_length(buf));
+  out = open_memstream((char**)&sexp_string_data(buf), (size_t*)&sexp_string_length(buf));
   res = sexp_make_input_port(ctx, out, SEXP_FALSE);
   sexp_port_cookie(res) = buf;
   return res;
@@ -638,7 +638,8 @@ sexp sexp_make_output_string_port (sexp ctx) {
 sexp sexp_get_output_string (sexp ctx, sexp port) {
   sexp cookie = sexp_port_cookie(port);
   fflush(sexp_port_stream(port));
-  return sexp_substring(cookie,
+  return sexp_substring(ctx,
+                        cookie,
                         sexp_make_integer(0),
                         sexp_make_integer(sexp_string_length(cookie)));
 }