diff --git a/Makefile b/Makefile
index 4202c35..4a2ef02 100644
--- a/Makefile
+++ b/Makefile
@@ -14,6 +14,7 @@
 include Makefile.in
 
 CFLAGS ?= -g -Wall
+LDFLAGS += -lz
 
 PROG=risu
 SRCS=risu.c comms.c risu_$(ARCH).c risu_reginfo_$(ARCH).c
@@ -31,7 +32,7 @@ all: $(PROG) $(BINS)
 dump: $(RISU_ASMS)
 
 $(PROG): $(OBJS)
-	$(CC) $(STATIC) $(CFLAGS) -o $@ $^
+	$(CC) $(STATIC) $(CFLAGS) -o $@ $^ $(LDFLAGS) 
 
 %.risu.asm: %.risu.bin
 	${OBJDUMP} -b binary -m $(ARCH) -D $^ > $@
diff --git a/configure b/configure
index f81bdb5..d11680f 100755
--- a/configure
+++ b/configure
@@ -6,6 +6,10 @@ compile() {
     $CC $CFLAGS -c -o ${1}.o ${1}.c 2>/dev/null
 }
 
+link() {
+    $LD $LDFLAGS -l${2} -o ${1} ${1}.o 2>/dev/null
+}
+
 check_define() {
     c=${tmp_dir}/check_define_${1}
     cat > ${c}.c <<EOF
@@ -34,6 +38,50 @@ guess_arch() {
     fi
 }
 
+check_type() {
+    c=${tmp_dir}/check_type_${1}
+    cat > ${c}.c <<EOF
+#include <inttypes.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+int main(void) { $1 thisone; return 0; }
+EOF
+    compile $c
+}
+
+check_lib() {
+    c=${tmp_dir}/check_lib${1}
+    cat > ${c}.c <<EOF
+#include <stdint.h>
+#include <$2.h>
+
+int main(void) { $3; return 0; }
+EOF
+    compile $c && link $c $1
+}
+
+generate_config() {
+    cfg=config.h
+    echo "generating config.h..."
+
+    echo "/* config.h - generated by the 'configure' script */" > $cfg
+    echo "#ifndef CONFIG_H" >> $cfg
+    echo "#define CONFIG_H 1" >> $cfg
+
+    if check_type uintptr_t ; then
+        echo "#define HAVE_UINTPTR_T 1" >> $cfg
+    fi
+    if check_type socklen_t ; then
+        echo "#define HAVE_SOCKLEN_T 1" >> $cfg
+    fi
+
+    echo "#endif /* CONFIG_H */" >> $cfg
+
+    echo "...done"
+}
+
 generate_makefilein() {
     m=Makefile.in
     echo "generating Makefile.in..."
@@ -93,6 +141,7 @@ done
 
 CC="${CC-${CROSS_PREFIX}gcc}"
 AS="${AS-${CROSS_PREFIX}as}"
+LD="${LD-${CROSS_PREFIX}ld}"
 OBJCOPY="${OBJCOPY-${CROSS_PREFIX}objcopy}"
 OBJDUMP="${OBJDUMP-${CROSS_PREFIX}objdump}"
 
@@ -100,6 +149,12 @@ if test "x${ARCH}" = "x"; then
     guess_arch
 fi
 
+if ! check_lib z zlib "zlibVersion()"; then
+    echo "Cannot find libz compression library"
+    exit 1
+fi
+
+generate_config
 generate_makefilein
 
 echo "type 'make' to start the build"
diff --git a/risu.c b/risu.c
index f36b4c6..1d58d4f 100644
--- a/risu.c
+++ b/risu.c
@@ -25,6 +25,7 @@
 #include <sys/mman.h>
 #include <fcntl.h>
 #include <string.h>
+#include <zlib.h>
 
 #include "risu.h"
 
@@ -32,6 +33,7 @@ void *memblock = 0;
 
 int apprentice_socket, master_socket;
 int trace_file = 0;
+gzFile gz_trace_file;
 
 sigjmp_buf jmpbuf;
 
@@ -52,13 +54,13 @@ void report_test_status(void *pc)
 
 int write_trace(void *ptr, size_t bytes)
 {
-   size_t res = write(trace_file, ptr, bytes);
+   size_t res = gzwrite(gz_trace_file, ptr, bytes);
    return res == bytes;
 }
 
 int read_trace(void *ptr, size_t bytes)
 {
-   size_t res = read(trace_file, ptr, bytes);
+   size_t res = gzread(gz_trace_file, ptr, bytes);
    return res == bytes;
 }
 
@@ -166,8 +168,9 @@ int master(int sock)
 {
    if (sigsetjmp(jmpbuf, 1))
    {
-      if (trace_file) {
-         close(trace_file);
+      if (trace_file)
+      {
+         gzclose(gz_trace_file);
          fprintf(stderr,"Done...\n");
          return 0;
       } else {
@@ -284,6 +287,7 @@ int main(int argc, char **argv)
      if (trace_fn)
        {
          trace_file = open(trace_fn, O_WRONLY|O_CREAT, S_IRWXU);
+         gz_trace_file = gzdopen(trace_file, "wb9");
        } else {
          fprintf(stderr, "master port %d\n", port);
          sock = master_connect(port);
@@ -295,6 +299,7 @@ int main(int argc, char **argv)
      if (trace_fn)
        {
          trace_file = open(trace_fn, O_RDONLY);
+         gz_trace_file = gzdopen(trace_file, "rb");
        } else {
          fprintf(stderr, "apprentice host %s port %d\n", hostname, port);
          sock = apprentice_connect(hostname, port);
