Merge #18297: build: Use pkg-config in BITCOIN_QT_CONFIGURE for all hosts including Windows

8a26848c460160e1279f26bc413f693a34e33b9d build: Fix m4 escaping (Hennadii Stepanov)
9123ec15db104397998f5084afc69403d2f9e4b8 build: Remove extra tokens warning (Hennadii Stepanov)
fded4f48c33742d7c790335c8de59c15b80d94e6 build: Remove duplicated QT_STATICPLUGIN define (Hennadii Stepanov)
05a93d5d96101b45d87571af5b772c7a1e82fd27 build: Fix indentation in bitcoin_qt.m4 (Hennadii Stepanov)
ddbb41931019ed4226af3df37874c7eb7cf570f1 build: Use pkg-config in BITCOIN_QT_CONFIGURE for all hosts (Hennadii Stepanov)
492971de35bab26346545f68365872211f458b00 build: Fix mingw pkgconfig file and dependency naming (Hennadii Stepanov)

Pull request description:

  This PR makes `bitcoin_qt.m4` to use `pkg-config` for all hosts and removes non-pkg-config paths from it. This is a step towards the idea which was clear [stated](https://github.com/bitcoin/bitcoin/pull/8314#issue-76644643) by Cory Fields:
  > I believe the consensus is to treat Windows like the others and require pkg-config across the board. We can drop all of the non-pkg-config paths, and simply AC_REQUIRE(PKG_PROG_PKG_CONFIG)

  There are two unsolved problems with this PR. If depends is built with `DEBUG=1` the `configure` script fails to pickup Qt:
  - for macOS host (similar to, but not the same as #16391)
  - for Windows host (regression)

  The fix is ~on its way~ submitted in #18298 (as a followup).

  Also this PR picks some small improvements from #17820.

ACKs for top commit:
  theuni:
    Code review ACK 8a26848c460160e1279f26bc413f693a34e33b9d
  dongcarl:
    Code Review ACK 8a26848c460160e1279f26bc413f693a34e33b9d
  laanwj:
    Code review ACK 8a26848c460160e1279f26bc413f693a34e33b9d

Tree-SHA512: 3b25990934b939121983df7707997b31d61063b1207d909f539d69494c7cb85212f353092956d09ecffebb9fef28b869914dd1216a596d102fcb9744bb5487f7

2 files changed, 14 insertions, 11 deletions

diff --git a/depends/config.site.in b/depends/config.site.in
index 103aa0d2ff..87a3379303 100644
--- a/depends/config.site.in
+++ b/depends/config.site.in
@@ -49,15 +49,6 @@ if test x@host_os@ = xdarwin; then
   PORT=no
 fi
 
-if test x@host_os@ = xmingw32; then
-  if test -z $with_qt_incdir; then
-    with_qt_incdir=$depends_prefix/include
-  fi
-  if test -z $with_qt_libdir; then
-    with_qt_libdir=$depends_prefix/lib
-  fi
-fi
-
 PATH=$depends_prefix/native/bin:$PATH
 PKG_CONFIG="`which pkg-config` --static"
 
diff --git a/depends/patches/qt/fix_qt_pkgconfig.patch b/depends/patches/qt/fix_qt_pkgconfig.patch
index 34302a9f2d..8c722ffb46 100644
--- a/depends/patches/qt/fix_qt_pkgconfig.patch
+++ b/depends/patches/qt/fix_qt_pkgconfig.patch
@@ -1,11 +1,23 @@
 --- old/qtbase/mkspecs/features/qt_module.prf
 +++ new/qtbase/mkspecs/features/qt_module.prf
-@@ -245,7 +245,7 @@
+@@ -264,7 +264,7 @@
  load(qt_targets)
  
  # this builds on top of qt_common
 -!internal_module:!lib_bundle:if(unix|mingw) {
-+unix|mingw {
++if(unix|mingw):!if(darwin:debug_and_release:CONFIG(debug, debug|release)) {
      CONFIG += create_pc
      QMAKE_PKGCONFIG_DESTDIR = pkgconfig
      host_build: \
+@@ -274,9 +274,9 @@
+     QMAKE_PKGCONFIG_INCDIR = $$[QT_INSTALL_HEADERS/raw]
+     QMAKE_PKGCONFIG_CFLAGS = -I${includedir}/$$MODULE_INCNAME
+     QMAKE_PKGCONFIG_NAME = $$replace(TARGET, ^Qt, "Qt$$QT_MAJOR_VERSION ")
+-    QMAKE_PKGCONFIG_FILE = $$replace(TARGET, ^Qt, Qt$$QT_MAJOR_VERSION)
++    QMAKE_PKGCONFIG_FILE = $$replace(TARGET, ^Qt, Qt$$QT_MAJOR_VERSION)$$qtPlatformTargetSuffix()
+     for(i, MODULE_DEPENDS): \
+-        QMAKE_PKGCONFIG_REQUIRES += $$replace(QT.$${i}.name, ^Qt, Qt$$section(QT.$${i}.VERSION, ., 0, 0))
++        QMAKE_PKGCONFIG_REQUIRES += $$replace(QT.$${i}.name, ^Qt, Qt$$section(QT.$${i}.VERSION, ., 0, 0))$$qtPlatformTargetSuffix()
+     isEmpty(QMAKE_PKGCONFIG_DESCRIPTION): \
+         QMAKE_PKGCONFIG_DESCRIPTION = $$replace(TARGET, ^Qt, "Qt ") module
+     pclib_replace.match = $$lib_replace.match