New, cleaner package repository structure.

Package repositories now look like this:

    top-level-dir/
        repo.yaml
        packages/
            libelf/
                package.py
            mpich/
                package.py
            ...

This leaves room at the top level for additional metadata, source,
per-repo configs, indexes, etc., and it makes it easy to see that
something is a spack repo (just look for repo.yaml and packages).

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

@@ -0,0 +1,109 @@
+import os
+from spack import *
+import os
+
+class Qt(Package):
+    """Qt is a comprehensive cross-platform C++ application framework."""
+    homepage = "http://qt.io"
+    list_url   = 'http://download.qt-project.org/official_releases/qt/'
+    list_depth = 2
+
+    version('5.4.0', 'e8654e4b37dd98039ba20da7a53877e6',
+            url='http://download.qt-project.org/official_releases/qt/5.4/5.4.0/single/qt-everywhere-opensource-src-5.4.0.tar.gz')
+    version('5.3.2', 'febb001129927a70174467ecb508a682',
+            url='http://download.qt.io/archive/qt/5.3/5.3.2/single/qt-everywhere-opensource-src-5.3.2.tar.gz')
+
+    version('5.2.1', 'a78408c887c04c34ce615da690e0b4c8',
+            url='http://download.qt.io/archive/qt/5.2/5.2.1/single/qt-everywhere-opensource-src-5.2.1.tar.gz')
+    version('4.8.6', '2edbe4d6c2eff33ef91732602f3518eb',
+            url="http://download.qt-project.org/official_releases/qt/4.8/4.8.6/qt-everywhere-opensource-src-4.8.6.tar.gz")
+
+    # Use system openssl for security.
+    #depends_on("openssl")
+
+    depends_on("glib")
+    depends_on("gtkplus")
+    depends_on("libxml2")
+    depends_on("zlib")
+    depends_on("dbus")
+    depends_on("libtiff")
+    depends_on("libpng")
+    depends_on("libmng")
+    depends_on("jpeg")
+
+    # Webkit
+    # depends_on("gperf")
+    # depends_on("flex")
+    # depends_on("bison")
+    # depends_on("ruby")
+    # depends_on("icu4c")
+
+    # OpenGL hardware acceleration
+    depends_on("mesa")
+    depends_on("libxcb")
+
+
+    def setup_dependent_environment(self, module, spec, dep_spec):
+        """Dependencies of Qt find it using the QTDIR environment variable."""
+        os.environ['QTDIR'] = self.prefix
+
+
+    def patch(self):
+        if self.spec.satisfies('@4'):
+            qmake_conf      = 'mkspecs/common/g++-base.conf'
+            qmake_unix_conf = 'mkspecs/common/g++-unix.conf'
+        elif self.spec.satisfies('@5'):
+            qmake_conf      = 'qtbase/mkspecs/common/g++-base.conf'
+            qmake_unix_conf = 'qtbase/mkspecs/common/g++-unix.conf'
+        else:
+            return
+
+        # Fix qmake compilers in the default mkspec
+        filter_file(r'^QMAKE_COMPILER *=.*$',  'QMAKE_COMPILER = cc', qmake_conf)
+        filter_file(r'^QMAKE_CC *=.*$',        'QMAKE_CC = cc',       qmake_conf)
+        filter_file(r'^QMAKE_CXX *=.*$',       'QMAKE_CXX = c++',     qmake_conf)
+        filter_file(r'^QMAKE_LFLAGS_NOUNDEF *\+?=.*$',  'QMAKE_LFLAGS_NOUNDEF =', qmake_unix_conf)
+
+
+    @property
+    def common_config_args(self):
+        return [
+            '-prefix', self.prefix,
+            '-v',
+            '-opensource',
+            '-opengl',
+            "-release",
+            '-shared',
+            '-confirm-license',
+            '-openssl-linked',
+            '-dbus-linked',
+            '-optimized-qmake',
+            '-no-openvg',
+            '-no-pch',
+            # NIS is deprecated in more recent glibc
+            "-no-nis"]
+    # Don't disable all the database drivers, but should
+    # really get them into spack at some point.
+
+
+    @when('@4')
+    def configure(self):
+        configure('-fast',
+                  '-no-webkit',
+                  *self.common_config_args)
+
+
+    @when('@5')
+    def configure(self):
+        configure('-no-eglfs',
+                  '-no-directfb',
+                  '-qt-xcb',
+                  # If someone wants to get a webkit build working, be my guest!
+                  '-skip', 'qtwebkit',
+                  *self.common_config_args)
+
+
+    def install(self, spec, prefix):
+        self.configure()
+        make()
+        make("install")