Avoid use of test -z in PKG_CHECK_VAR.

diff --git a/m4/pkgvar.m4 b/m4/pkgvar.m4
index 20a9a6a02c38109ab6a392e1a0a341a9c4be708c..b4e09ee3e301a1e4651b1860d6998db33319f8ea 100644 (file)
--- a/m4/pkgvar.m4
+++ b/m4/pkgvar.m4
@@ -10,13 +10,13 @@ See the pkg-config man page for more details.])
 
 pkg_fail=no
 AC_MSG_CHECKING([for $3])
-if test -z "$[]m4_toupper([$1][_$2])"; then
+if test x"$[]m4_toupper([$1][_$2])" = x; then
        _PKG_CONFIG([$1][_$2], [variable=$2], [$4])
 else
        pkg_cv_$1[]_$2="$[]m4_toupper([$1][_$2])"
 fi
 
-if test -z "[$pkg_cv_$1][_$2]"; then
+if test x"[$pkg_cv_$1][_$2]" = x; then
        if test $pkg_failed = yes; then
                _PKG_SHORT_ERRORS_SUPPORTED
                if test $_pkg_short_errors_supported = yes; then