Add qmake virtual provider (#38848)

etc/spack/defaults/packages.yaml

@@ -49,6 +49,7 @@ packages:
       pbs: [openpbs, torque]
       pil: [py-pillow]
       pkgconfig: [pkgconf, pkg-config]
+      qmake: [qt-base, qt]
       rpc: [libtirpc]
       scalapack: [netlib-scalapack, amdscalapack]
       sycl: [hipsycl]

lib/spack/spack/build_systems/qmake.py

@@ -28,7 +28,7 @@ class QMakePackage(spack.package_base.PackageBase):
 
     build_system("qmake")
 
-    depends_on("qt", type="build", when="build_system=qmake")
+    depends_on("qmake", type="build", when="build_system=qmake")
 
 
 @spack.builder.builder("qmake")

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

@@ -33,6 +33,8 @@ def get_list_url(qualname):
 
     maintainers("wdconinc", "sethrj")
 
+    provides("qmake")
+
     # Default dependencies for all qt-* components
     generator("ninja")
     depends_on("cmake@3.16:", type="build")

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

@@ -69,6 +69,8 @@ class Qt(Package):
     variant("tools", default=True, description="Build tools, including Qt Designer.")
     variant("webkit", default=False, description="Build the Webkit extension")
 
+    provides("qmake")
+
     # Patches for qt@3
     patch("qt3-accept.patch", when="@3")
     patch("qt3-headers.patch", when="@3")