Fix QT on Linux+clang (#13684)

* Add platform flag to QT for linux+clang

* Extend QT platform support to more compilers and systems

* Unify QT5 configure options

* fixup! Unify QT5 configure options

* fixup! Unify QT5 configure options

* fixup! Unify QT5 configure options

* Fix newer flake8 and mac qt5 configure

var/spack/repos/builtin/packages/qt/package.py

@@ -169,6 +169,9 @@ class Qt(Package):
 
     use_xcode = True
 
+    # Mapping for compilers in the QT 'mkspecs'
+    compiler_mapping = {'intel': 'icc', 'clang': 'clang-libc++', 'gcc': 'g++'}
+
     def url_for_version(self, version):
         # URL keeps getting more complicated with every release
         url = self.list_url
@@ -415,16 +418,31 @@ def common_config_args(self):
         if MACOS_VERSION:
             config_args.append('-{0}framework'.format(
                 '' if '+framework' in self.spec else 'no-'))
-        if '@5:' in self.spec and MACOS_VERSION:
-            config_args.extend([
-                '-no-xcb-xlib',
-                '-no-pulseaudio',
-                '-no-alsa',
-            ])
-            if self.spec.satisfies('@:5.11'):
-                config_args.append('-no-xinput2')
 
-        # FIXME: else: -system-xcb ?
+        # Note: QT defaults to the following compilers
+        #  QT4 mac: gcc
+        #  QT5 mac: clang
+        #  linux: gcc
+        # In QT4, unsupported compilers lived under an 'unsupported'
+        # subdirectory but are now in the main platform directory.
+        spec = self.spec
+        cname = spec.compiler.name
+        cname = self.compiler_mapping.get(cname, cname)
+        is_new_qt = spec.satisfies('@5:')
+        platform = None
+        if MACOS_VERSION:
+            if is_new_qt and cname != "clang-libc++":
+                platform = 'macx-' + cname
+            elif not is_new_qt and cname != "g++":
+                platform = 'unsupported/macx-' + cname
+        elif cname != 'g++':
+            if is_new_qt:
+                platform = 'linux-' + cname
+            else:
+                platform = 'unsupported/linux-' + cname
+
+        if platform is not None:
+            config_args.extend(['-platform', platform])
 
         return config_args
 
@@ -472,51 +490,56 @@ def configure(self, spec, prefix):
             sdkpath = which('xcrun')('--show-sdk-path', output=str).strip()
             config_args.extend([
                 '-cocoa',
-                '-platform', 'unsupported/macx-clang-libc++',
                 '-sdk', sdkpath])
 
         configure(*config_args)
 
-    @when('@5.0:5.6')
+    @when('@5')
-    def configure(self, spec, prefix):
-        webkit_args = [] if '+webkit' in spec else ['-skip', 'qtwebkit']
-        configure('-no-eglfs',
-                  '-no-directfb',
-                  '-{0}gtkstyle'.format('' if '+gtk' in spec else 'no-'),
-                  *(webkit_args + self.common_config_args))
-
-    @when('@5.7:')
     def configure(self, spec, prefix):
         config_args = self.common_config_args
+        version = self.version
 
-        if not MACOS_VERSION:
+        config_args.extend([
+            '-no-eglfs',
+            '-no-directfb',
+            '-{0}gtk{1}'.format(
+                '' if '+gtk' in spec else 'no-',
+                '' if version >= Version('5.8') else 'style')
+        ])
+
+        if MACOS_VERSION:
             config_args.extend([
-                '-system-xcb',
+                '-no-xcb-xlib',
+                '-no-pulseaudio',
+                '-no-alsa',
             ])
+            if version < Version('5.12'):
+                config_args.append('-no-xinput2')
+        else:
+            # Linux-only QT5 dependencies
+            config_args.append('-system-xcb')
 
         if '~webkit' in spec:
             config_args.extend([
-                '-skip', 'webengine',
+                '-skip',
+                'webengine' if version >= Version('5.7') else 'qtwebkit',
             ])
 
-        if '~opengl' in spec and spec.satisfies('@5.10:'):
+        if spec.satisfies('@5.7'):
-            config_args.extend([
+            config_args.extend(['-skip', 'virtualkeyboard'])
-                '-skip', 'webglplugin',
-            ])
 
-        if self.version > Version('5.8'):
+        if version >= Version('5.8'):
             # relies on a system installed wayland, i.e. no spack package yet
             # https://wayland.freedesktop.org/ubuntu16.04.html
             # https://wiki.qt.io/QtWayland
             config_args.extend(['-skip', 'wayland'])
 
-        if spec.satisfies('@5.7'):
+        if version >= Version('5.10') and '~opengl' in spec:
-            config_args.extend(['-skip', 'virtualkeyboard'])
+            config_args.extend([
+                '-skip', 'webglplugin',
+            ])
 
-        configure('-no-eglfs',
+        configure(*config_args)
-                  '-no-directfb',
-                  '-{0}gtk'.format('' if '+gtk' in spec else 'no-'),
-                  *config_args)
 
     def build(self, spec, prefix):
         make()