diff --git a/acinclude.m4 b/acinclude.m4
index ed48a6eb3a..035451da8b 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1336,9 +1336,15 @@ AC_DEFUN([CURL_TRACE_PCDIR], [
   dnl Example pkgconf line:
   dnl   libpkgconf/pkg.c:746 [pkgconf_pkg_t *pkgconf_pkg_try_specific_path(pkgconf_client_t *, [...]*)]: trying path: /usr/local/lib/pkgconfig for libngtcp2_crypto_gnutls
   dnl Rest of strings are for catching classic pkg-config lines.
-  trc=`CURL_EXPORT_PCDIR([$2]) dnl
+  trc=`CURL_EXPORT_PCDIR([$2])
+    if test -n "$PKG_CONFIG_LIBDIR"; then
+      echo "PKG_CONFIG_LIBDIR: '$PKG_CONFIG_LIBDIR'"
+    fi
+    if test -n "$PKG_CONFIG_PATH"; then
+      echo "PKG_CONFIG_PATH: '$PKG_CONFIG_PATH'"
+    fi
     $PKGCONFIG --exists --debug $1 2>&1 | $EGREP '(trying path:|Adding directory|Looking for|Scanning directory|Cannot open directory)' | $SED 's/^.*trying path:/trying path:/'`
-  msg=`CURL_EXPORT_PCDIR([$2]) dnl
+  msg=`CURL_EXPORT_PCDIR([$2])
     $PKGCONFIG --exists --print-errors $1 2>&1`
   if test -n "$msg"; then
     trc=`echo "$trc"; echo '==== error:'; echo "$msg"`