Merge #18298: build: Fix Qt processing of configure script for depends with DEBUG=1

76f52e3da3 build: Fix Qt processing of configure script for depends with DEBUG=1 (Hennadii Stepanov)

Pull request description:

  This PR:
  - makes the `configure` script correctly pickup Qt if depends is built with `DEBUG=1`:
      - for Windows -- fix #19266
      - for macOS -- fix #16391
  - is an alternative to #18117 (without downsides)

ACKs for top commit:
  fanquake:
    ACK 76f52e3da3. Tested native darwin, and darwin/win cross compile with `DEBUG=1`.

Tree-SHA512: 8fde99302b4b06faf109315bddba9e3063b156c50f8f9863c2bd51718538c719429a63fdced071730c18022f2e559d3b25c1dcec3efa81fe79f657253680956a

depends/config.site.in

@@ -54,6 +54,10 @@ if test -z "$with_gui" && test -n "@no_qt@"; then
   with_gui=no
 fi
 
+if test -n "@debug@" && test -z "@no_qt@" && test "x$with_gui" != xno; then
+  with_gui=qt5_debug
+fi
+
 if test -z "$enable_zmq" && test -n "@no_zmq@"; then
   enable_zmq=no
 fi