qt6: Add todo about prefix and adjust docs

[Greg Troxel <gdt%lexort.com@localhost>]

Module Name:	pkgsrc-wip
Committed By:	Greg Troxel <gdt%lexort.com@localhost>
Pushed By:	gdt
Date:		Mon Aug 9 18:44:52 2021 -0400
Changeset:	f0499245ac8edff94a77dad3a0c34aaf5c4cea0c

Modified Files:
	qt6-qtbase/DESCR
	qt6-qtbase/TODO
	qt6-qtbase/buildlink3.mk
	qt6/Makefile.common
Removed Files:
	qt6-qtbase/MESSAGE

Log Message:
qt6: Add todo about prefix and adjust docs

 - Document the subprefix scheme in Makefile.common
 - Hint in qt6-qtbase's DESCR that a non-standard prefix is used
 - Add TODOs to use the same subprefix definition in buildlink3.mk
   rather than hardcoding a copy
 - Drop MESSAGE because it is just documentation (contents added above)

To see a diff of this commit:
https://wip.pkgsrc.org/cgi-bin/gitweb.cgi?p=pkgsrc-wip.git;a=commitdiff;h=f0499245ac8edff94a77dad3a0c34aaf5c4cea0c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

diffstat:
 qt6-qtbase/DESCR         |  2 +-
 qt6-qtbase/MESSAGE       | 18 ------------------
 qt6-qtbase/TODO          |  5 +++--
 qt6-qtbase/buildlink3.mk |  1 +
 qt6/Makefile.common      |  7 +++++++
 5 files changed, 12 insertions(+), 21 deletions(-)

diffs:
diff --git a/qt6-qtbase/DESCR b/qt6-qtbase/DESCR
index 30c172aa90..1303c02d18 100644
--- a/qt6-qtbase/DESCR
+++ b/qt6-qtbase/DESCR
@@ -12,4 +12,4 @@ Simply recompile your source code on the platform you want.
 Qt cuts down the complexity in implementing large and complex systems. Its
 ingenious signal-slot technology enables true component programming.
 
-This package tracks Qt6 qtbase submodule.
+This package tracks Qt6 qtbase submodule and installs into a qt6 subprefix.
diff --git a/qt6-qtbase/MESSAGE b/qt6-qtbase/MESSAGE
deleted file mode 100644
index 0d62cf1846..0000000000
--- a/qt6-qtbase/MESSAGE
+++ /dev/null
@@ -1,18 +0,0 @@
-===========================================================================
-$NetBSD$
-
-To allow this package to coexist with other versions of Qt
-it has been installed in ${PREFIX}/qt6/{bin,include,lib,doc} etc.
-
-You should be able to select this version of Qt when compiling
-programs which use it by ensuring that
-
-1) QTDIR is set to ${PREFIX}/qt6
-
-2) Use the "configure" argument "--with-qt-dir=${PREFIX}/qt6"
-
-3) Use the "cmake" argument "-DCMAKE_SYSTEM_PREFIX_PATH:PATH=${PREFIX}/qt6"
-
-4) you may also have to put ${PREFIX}/qt6/bin in your PATH
-
-===========================================================================
diff --git a/qt6-qtbase/TODO b/qt6-qtbase/TODO
index 76823d23b1..56fc77ed87 100644
--- a/qt6-qtbase/TODO
+++ b/qt6-qtbase/TODO
@@ -1,2 +1,3 @@
-test builds for Darwin
-remove unneeded stuff in makefiles from qt5
+ - test builds for Darwin
+ - remove unneeded stuff in makefiles from qt5
+ - reuse prefix definition from ../qt6/Makefile.common
diff --git a/qt6-qtbase/buildlink3.mk b/qt6-qtbase/buildlink3.mk
index e14c529a58..ba8df82688 100644
--- a/qt6-qtbase/buildlink3.mk
+++ b/qt6-qtbase/buildlink3.mk
@@ -12,6 +12,7 @@ BUILDLINK_INCDIRS.qt6-qtbase+=	qt6/include
 BUILDLINK_LIBDIRS.qt6-qtbase+=	qt6/lib
 BUILDLINK_LIBDIRS.qt6-qtbase+=	qt6/plugins
 
+# \todo Fix duplication with prefix coded in Makefile.common
 QTDIR=		${BUILDLINK_PREFIX.qt6-qtbase}/qt6
 CMAKE_PREFIX_PATH+=	${QTDIR}
 
diff --git a/qt6/Makefile.common b/qt6/Makefile.common
index 28cc17a570..8e135c747f 100644
--- a/qt6/Makefile.common
+++ b/qt6/Makefile.common
@@ -14,6 +14,13 @@ MAINTAINER?=	pkgsrc-users%NetBSD.org@localhost
 HOMEPAGE=	https://www.qt.io/
 LICENSE=	gnu-lgpl-v2.1 AND gnu-lgpl-v3 AND gnu-gpl-v2 AND gnu-gpl-v3
 
+# The qt6 packages install with prefix being a qt6 subdirectory, so
+# that it can be installed in parallel with qt5, rather than being an
+# alternative.  Various things may be necessary to use it from outside
+# of pkgsrc:
+#   1) Use the "configure" argument "--with-qt-dir=${PREFIX}/qt6"
+#   2) Use the "cmake" argument "-DCMAKE_SYSTEM_PREFIX_PATH:PATH=${PREFIX}/qt6"
+#   3) you may also have to put ${PREFIX}/qt6/bin in your PATH
 QTPREFIX=	${PREFIX}/qt6
 
 GCC_REQD+=	9