diff --git a/configure.in b/configure.in
index fa68673e..d9fee5b9 100644
--- a/configure.in
+++ b/configure.in
@@ -2,7 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 AC_INIT(src/backtrace.c)
 AC_CONFIG_AUX_DIR(aux)
 AC_CANONICAL_SYSTEM
-AM_INIT_AUTOMAKE(libunwind, 0.2-pre4)
+AM_INIT_AUTOMAKE(libunwind, 0.2-pre5)
 AM_MAINTAINER_MODE
 AM_CONFIG_HEADER(include/config.h)
 
@@ -45,6 +45,7 @@ AM_CONDITIONAL(REMOTE_ONLY, test x$target_arch != x$build_arch)
 AM_CONDITIONAL(ARCH_IA64, test x$target_arch = xia64)
 AM_CONDITIONAL(ARCH_HPPA, test x$target_arch = xhppa)
 AM_CONDITIONAL(ARCH_X86, test x$target_arch = xx86)
+AM_CONDITIONAL(OS_LINUX, expr x$target_os : xlinux >/dev/null)
 
 if test x$target_arch != x$build_arch; then
   CPPFLAGS="${CPPFLAGS} -DUNW_REMOTE_ONLY"
@@ -67,7 +68,7 @@ fi
 ASFLAGS="${ASFLAGS} ${CPPFLAGS}"
 
 if test x$GCC = xyes; then
-  CFLAGS="${CFLAGS} -Wall"
+  CFLAGS="${CFLAGS} -Wall -Wsign-compare"
 fi
 
 arch="$target_arch"