build, qt: Fix lib paths in *.pc files

See:
- QTBUG-72903, commit 9864d2c6f3b628ca9f07a56b197e77bd43931cca
- QTBUG-78873, commit e55a61a77f0c87c05661a0335dfdb12673c6a27f

Could be dropped for Qt 5.14+.

depends/packages/qt.mk

@@ -9,7 +9,7 @@ $(package)_qt_libs=corelib network widgets gui plugins testlib
 $(package)_patches=fix_qt_pkgconfig.patch mac-qmake.conf fix_no_printer.patch no-xlib.patch
 $(package)_patches+= fix_android_qmake_conf.patch fix_android_jni_static.patch dont_hardcode_pwd.patch
 $(package)_patches+= drop_lrelease_dependency.patch no_sdk_version_check.patch
-$(package)_patches+= fix_qpainter_non_determinism.patch
+$(package)_patches+= fix_qpainter_non_determinism.patch fix_lib_paths.patch
 
 $(package)_qttranslations_file_name=qttranslations-$($(package)_suffix)
 $(package)_qttranslations_sha256_hash=e1de58ed108b7e0a138815ea60fd46a2c4e1fc31396a707e5630e92de79c53de
@@ -226,6 +226,7 @@ define $(package)_preprocess_cmds
   patch -p1 -i $($(package)_patch_dir)/no-xlib.patch && \
   patch -p1 -i $($(package)_patch_dir)/fix_qpainter_non_determinism.patch &&\
   patch -p1 -i $($(package)_patch_dir)/no_sdk_version_check.patch && \
+  patch -p1 -i $($(package)_patch_dir)/fix_lib_paths.patch && \
   sed -i.old "s|updateqm.commands = \$$$$\$$$$LRELEASE|updateqm.commands = $($(package)_extract_dir)/qttools/bin/lrelease|" qttranslations/translations/translations.pro && \
   mkdir -p qtbase/mkspecs/macx-clang-linux &&\
   cp -f qtbase/mkspecs/macx-clang/qplatformdefs.h qtbase/mkspecs/macx-clang-linux/ &&\

depends/patches/qt/fix_lib_paths.patch

@@ -0,0 +1,193 @@
+--- old/qtbase/mkspecs/common/mac.conf
++++ new/qtbase/mkspecs/common/mac.conf
+@@ -14,7 +14,6 @@
+ 
+ QMAKE_RESOURCE          = /Developer/Tools/Rez
+ QMAKE_EXTENSION_SHLIB   = dylib
+-QMAKE_EXTENSIONS_AUX_SHLIB = tbd
+ QMAKE_LIBDIR            =
+ 
+ # sdk.prf will prefix the proper SDK sysroot
+
+--- old/qtbase/mkspecs/features/qmake_use.prf
++++ new/qtbase/mkspecs/features/qmake_use.prf
+@@ -22,6 +22,8 @@
+         !defined(QMAKE_LIBS_$$nu, var): \
+             error("Library '$$lower($$replace(nu, _, -))' is not defined.")
+ 
++        QMAKE_LIBDIR += $$eval(QMAKE_LIBDIR_$$nu)
++
+         debug: \
+             LIBS$${suffix} += $$eval(QMAKE_LIBS_$${nu}_DEBUG) $$eval(QMAKE_LIBS_$$nu)
+         else: \
+
+--- old/qtbase/mkspecs/features/qt_configure.prf
++++ new/qtbase/mkspecs/features/qt_configure.prf
+@@ -526,98 +526,23 @@
+     return($$sysrootified)
+ }
+ 
+-# libs-var, libs, in-paths, out-paths-var
++# libs-var, libs, in-paths
+ defineTest(qtConfResolveLibs) {
+-    ret = true
+-    paths = $$3
+-    out =
+-    copy = false
+-    for (l, 2) {
+-        $$copy {
+-            copy = false
+-            out += $$l
+-        } else: equals(l, "-s") {
+-            # em++ flag to link libraries from emscripten-ports; passed on literally.
+-            copy = true
+-            out += $$l
+-        } else: contains(l, "^-L.*") {
+-            lp = $$replace(l, "^-L", )
+-            gcc: lp = $$qtGccSysrootifiedPath($$lp)
+-            !exists($$lp/.) {
+-                qtLog("Library path $$val_escape(lp) is invalid.")
+-                ret = false
+-            } else {
+-                paths += $$lp
+-            }
+-        } else: contains(l, "^-l.*") {
+-            lib = $$replace(l, "^-l", )
+-            lcan =
+-            integrity:contains(lib, "^.*\\.a") {
+-                # INTEGRITY compiler searches for exact filename
+-                # if -l argument has .a suffix
+-                lcan += $${lib}
+-            } else: contains(lib, "^:.*") {
+-                # Use exact filename when -l:filename syntax is used.
+-                lib ~= s/^://
+-                lcan += $${lib}
+-            } else: unix {
+-                # Under UNIX, we look for actual shared libraries, in addition
+-                # to static ones.
+-                shexts = $$QMAKE_EXTENSION_SHLIB $$QMAKE_EXTENSIONS_AUX_SHLIB
+-                for (ext, shexts) {
+-                    lcan += $${QMAKE_PREFIX_SHLIB}$${lib}.$${ext}
+-                }
+-                lcan += \
+-                    $${QMAKE_PREFIX_STATICLIB}$${lib}.$${QMAKE_EXTENSION_STATICLIB}
+-            } else {
+-                # Under Windows, we look only for static libraries, as even for DLLs
+-                # one actually links against a static import library.
+-                mingw {
+-                    lcan += \
+-                        # MinGW supports UNIX-style library naming in addition to
+-                        # the MSVC style.
+-                        lib$${lib}.dll.a lib$${lib}.a \
+-                        # Fun fact: prefix-less libraries are also supported.
+-                        $${lib}.dll.a $${lib}.a
+-                }
+-                lcan += $${lib}.lib
+-            }
+-            l = $$qtConfFindInPathList($$lcan, $$paths $$EXTRA_LIBDIR $$QMAKE_DEFAULT_LIBDIRS)
+-            isEmpty(l) {
+-                qtLog("None of [$$val_escape(lcan)] found in [$$val_escape(paths)] and global paths.")
+-                ret = false
+-            } else {
+-                out += $$l
+-            }
+-        } else {
+-            out += $$l
+-        }
+-    }
+-    $$1 = $$out
++    for (path, 3): \
++        pre_lflags += -L$$path
++    $$1 = $$pre_lflags $$2
+     export($$1)
+-    !isEmpty(4) {
+-        $$4 = $$paths
+-        export($$4)
+-    }
+-    return($$ret)
+-}
+-
+-# source-var
+-defineTest(qtConfResolveAllLibs) {
+-    ret = true
+-    !qtConfResolveLibs($${1}.libs, $$eval($${1}.libs), , $${1}.libdirs): \
+-        ret = false
+-    for (b, $${1}.builds._KEYS_): \
+-        !qtConfResolveLibs($${1}.builds.$${b}, $$eval($${1}.builds.$${b}), $$eval($${1}.libdirs), ): \
+-            ret = false
+-    return($$ret)
++    return(true)
+ }
+ 
+ # libs-var, in-paths, libs
+ defineTest(qtConfResolvePathLibs) {
+     ret = true
+-    gcc: 2 = $$qtGccSysrootifiedPaths($$2)
+-    for (libdir, 2) {
++    gcc: \
++        local_paths = $$qtGccSysrootifiedPaths($$2)
++    else: \
++        local_paths = $$2
++    for (libdir, local_paths) {
+         !exists($$libdir/.) {
+             qtLog("Library path $$val_escape(libdir) is invalid.")
+             ret = false
+@@ -667,8 +592,11 @@
+ # includes-var, in-paths, test-object-var
+ defineTest(qtConfResolvePathIncs) {
+     ret = true
+-    gcc: 2 = $$qtGccSysrootifiedPaths($$2)
+-    for (incdir, 2) {
++    gcc: \
++        local_paths = $$qtGccSysrootifiedPaths($$2)
++    else: \
++        local_paths = $$2
++    for (incdir, local_paths) {
+         !exists($$incdir/.) {
+             qtLog("Include path $$val_escape(incdir) is invalid.")
+             ret = false
+@@ -727,6 +655,7 @@
+         vars += $$eval(config.commandline.rev_assignments.$${iv})
+         defined(config.input.$${iv}, var) {
+             eval($${1}.builds.$${b} = $$eval(config.input.$${iv}))
++            export($${1}.builds.$${b})
+             $${1}.builds._KEYS_ *= $${b}
+             any = true
+         } else {
+@@ -741,11 +670,14 @@
+         export($${1}.builds._KEYS_)
+         # we also reset the generic libs, to avoid surprises.
+         $${1}.libs =
++        export($${1}.libs)
+     }
+ 
+     # direct libs. overwrites inline libs.
+-    defined(config.input.$${input}.libs, var): \
++    defined(config.input.$${input}.libs, var) {
+         eval($${1}.libs = $$eval(config.input.$${input}.libs))
++        export($${1}.libs)
++    }
+ 
+     includes = $$eval(config.input.$${input}.incdir)
+ 
+@@ -754,6 +686,7 @@
+     !isEmpty(prefix) {
+         includes += $$prefix/include
+         $${1}.libs = -L$$prefix/lib $$eval($${1}.libs)
++        export($${1}.libs)
+     }
+ 
+     libdir = $$eval(config.input.$${input}.libdir)
+@@ -762,11 +695,9 @@
+         for (ld, libdir): \
+             libs += -L$$ld
+         $${1}.libs = $$libs $$eval($${1}.libs)
++        export($${1}.libs)
+     }
+ 
+-    !qtConfResolveAllLibs($$1): \
+-        return(false)
+-
+     !qtConfResolvePathIncs($${1}.includedir, $$includes, $$2): \
+         return(false)
+