diff --git a/tests/test-headers.sh b/tests/test-headers.sh
index ae483744d7..0cdda170de 100644
--- a/tests/test-headers.sh
+++ b/tests/test-headers.sh
@@ -1,44 +1,44 @@
 #!/bin/sh
 #
 # Check public headers for c++ compatibility and consistent protection #ifdefs
 #
 #
 
 INCLUDE_FILES="`find ../include/ -name \*.h -a \! -name \*internal.h`"
 
 for i in $INCLUDE_FILES
 do
     NAME="`echo $i | cut -c12-`"
 
     # config.h is generated by autoconf
     # gettext.h is supplied by gettext
     if [ "$NAME" = "config.h" ] || [ "$NAME" = "gettext.h" ]
     then
         continue
     fi
     PROTECT="PCMK__`echo $NAME | tr '[:lower:]' '[:upper:]' | tr '/\.' '_' |tr '-' '_' `"
     PROTECT=`echo $PROTECT|sed 's/_H/__H/'`  # PCMK uses double underscore for .h (eg NAME__H)
 
     echo "#include <$NAME>" > _test_file.c
     echo "#ifndef $PROTECT" >> _test_file.c
     echo "#error no header protector in file $i" >> _test_file.c
     echo "#endif" >> _test_file.c
     echo "int main(void) {return 0;}" >> _test_file.c
 
     # Not including ${CFLAGS} because it seems to break header detection. But we're not really building here
     ${CC} -I ../include -DHAVE_CONFIG_H ${CPPFLAGS} ${LIBS} _test_file.c -o /dev/null
     if [ $? -ne 0 ]
     then
         exit 1
     fi
-    if [ "$CXX" ]
+    if [ "$CXX" ] && [ command -v "$CXX" >/dev/null 2>&1 ]
     then
         ${CXX} ${CXXFLAGS} ${CPPFLAGS} ${LIBS} -I ../include _test_file.c -o /dev/null
         if [ $? -ne 0 ]
         then
             exit 1
         fi
         echo -n
     fi
     rm -f _test_file.c
 done