diff --git a/mozilla/old-configure.in b/mozilla/old-configure.in

index 924a185..b683375 100644

--- a/mozilla/old-configure.in

+++ b/mozilla/old-configure.in

@@ -500,7 +500,7 @@ CFLAGS="$CFLAGS $HARDENING_CFLAGS"

 CPPFLAGS="$CPPFLAGS $HARDENING_CFLAGS"

 CXXFLAGS="$CXXFLAGS $HARDENING_CFLAGS"

-if test "$GNU_CC" -o test -n "${CLANG_CC}${CLANG_CL}"; then

+if test "$GNU_CC" || test -n "${CLANG_CC}${CLANG_CL}"; then

    CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"

    CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2"

    CXXFLAGS="$CXXFLAGS -D_FORTIFY_SOURCE=2"