diff --git a/configure.ac b/configure.ac
index b4966d3..533f5e3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -32,7 +32,7 @@ fi
 # check for libraries that have pkg-config files installed
 PKG_CHECK_MODULES(ORTP, ortp >= 0.21.0,[found_ortp=true],foo=bar)
 PKG_CHECK_MODULES(MEDIASTREAMER, mediastreamer >= 2.8.99,[found_ms2=true],foo=bar)
-AM_CONDITIONAL(BUILD_MSBCG729, test x$found_ms2x$found_ortp = xtruextrue)
+AM_CONDITIONAL(BUILD_MSBCG729, test x${found_ms2}x${found_ortp} = xtruextrue)
 
 # Create the following files from their .in counterparts
 AC_CONFIG_FILES([