Respect environment variables for PKG_CHECK_VAR.

diff --git a/m4/pkgvar.m4 b/m4/pkgvar.m4
index 4b7fa9bd8c4c4e9293d76cfe60cce1c064bfdca9..20a9a6a02c38109ab6a392e1a0a341a9c4be708c 100644 (file)
--- a/m4/pkgvar.m4
+++ b/m4/pkgvar.m4
@@ -10,7 +10,12 @@ See the pkg-config man page for more details.])
 
 pkg_fail=no
 AC_MSG_CHECKING([for $3])
-_PKG_CONFIG([$1][_$2], [variable=$2], [$4])
+if test -z "$[]m4_toupper([$1][_$2])"; 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 $pkg_failed = yes; then
                _PKG_SHORT_ERRORS_SUPPORTED