diff --git a/configure.ac b/configure.ac
index ee6693d..45300c0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -337,7 +337,7 @@ if test $compiler_xlc = yes -a "$powerpc_darwin" = true; then
   AC_DEFINE([DARWIN_DONT_PARSE_STACK], 1, [See doc/README.macros.])
 fi
 
-if test "$GCC" == yes; then
+if test "$GCC" = yes; then
   # Disable aliasing optimization unless forced to.
   AC_MSG_CHECKING([whether gcc supports -fno-strict-aliasing])
   ac_cv_fno_strict_aliasing=no
@@ -442,8 +442,8 @@ esac
 AC_MSG_RESULT($enable_shared)
 
 # Compile with GC_DLL defined unless building static libraries.
-if test "${enable_shared}" == yes; then
-  if test "${enable_static}" == no; then
+if test "${enable_shared}" = yes; then
+  if test "${enable_static}" = no; then
     AC_DEFINE(GC_DLL)
     # FIXME: Also pass -fvisibility=hidden option if GCC v4+ and not Win32.
   fi
@@ -707,7 +707,7 @@ if test -n "${with_cross_host}"; then
              [Define to tune the collector for small heap sizes.])
 fi
 
-if test "$enable_gc_debug" == "no"; then
+if test "$enable_gc_debug" = "no"; then
    AC_DEFINE([NO_DEBUGGING], 1,
              [Disable debugging, like GC_dump and its callees.])
 fi