gbuild: introduce plugin + loader concepts

This introduces two concepts: a plugin and its loader (library)

LO currrently has dependency cycles for some libraries. There is
scui, which depends on sc, while sc dlopen's scui. There are the
various vclplug_*, i18npool plugins, filters/gie, acc, etc.

Usually these plugins link to their loader library, because they
use its symbols. But as a result there is no sensible way to
express the runtime dependency of loaders on the plugins.

In GNU libtool plugins are called modules and they are implemented
in an IMHO more sensible way by allowing missing symbols at link
time. This way you can have a dependency from the loader library
to its plugins, as the plugins don't depend on the loader, but you
lose the link time detection of missing symbols.

While this is in theory possible in LO too, LO currently has
plugins, like acc (accessibility), loaded by tk (toolkit), which
depends on svt (svtools), which itself depends on tk, so dropping
the tk dependency for acc on its own doesn't help :-(

And while the dependency of the plugins on their loader is fine
for the shared / DYNLOADING build, for the "static" builds you
must (somehow) link the plugins into the executables.

I also codeified a few rules into the build system along with it:
* just plugins are allowed to depend / link other plugins
* plugins aren't allowed to be linked into the merge lib
* plugin loaders are "limited" to libraries

At the high level, this is implemented via new gbuild calls:
* gb_Library_set_plugin_for,lib,loader: declare a library to be a
plugin of a loader library and add a dependeny from the plugin
library to the loader library
* gb_Library_set_plugin_for_nodep,lib,loader: ^^^^ without adding
the library dependeny
* gb_Helper_register_plugins_for_install: "plugin" replacement for
gb_Helper_register_libraries_for_install to implement some
additional checks in the build system

In the end this patch just adds a bit syntactic sugar and nothing
changes for any build.

Change-Id: I7b01d9c384cbc5838bd2cc93aff18e4868939d6e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/126163
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

9 files changed, 18 insertions, 9 deletions

diff --git a/vcl/Library_vclplug_gen.mk b/vcl/Library_vclplug_gen.mk
index 3ebf80034c91..73f5464d7362 100644
--- a/vcl/Library_vclplug_gen.mk
+++ b/vcl/Library_vclplug_gen.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_gen))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_gen,vcl))
+
 $(eval $(call gb_Library_set_include,vclplug_gen,\
     $$(INCLUDE) \
     -I$(SRCDIR)/vcl/inc \
@@ -33,7 +35,6 @@ $(eval $(call gb_Library_use_sdk_api,vclplug_gen))
 $(eval $(call gb_Library_use_common_precompiled_header,vclplug_gen))
 
 $(eval $(call gb_Library_use_libraries,vclplug_gen,\
-    vcl \
     tl \
     utl \
     sot \
diff --git a/vcl/Library_vclplug_gtk3.mk b/vcl/Library_vclplug_gtk3.mk
index 09374b635284..702dedc3b43a 100644
--- a/vcl/Library_vclplug_gtk3.mk
+++ b/vcl/Library_vclplug_gtk3.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_gtk3))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_gtk3,vcl))
+
 # Silence deprecation warnings wholesale as long as vcl/unx/gtk3/*.cxx just
 # forward to vcl/unx/gtk/*.cxx:
 $(eval $(call gb_Library_add_cxxflags,vclplug_gtk3, \
@@ -54,7 +56,6 @@ $(eval $(call gb_Library_add_libs,vclplug_gtk3,\
 ))
 
 $(eval $(call gb_Library_use_libraries,vclplug_gtk3,\
-    vcl \
     svl \
     tl \
     utl \
diff --git a/vcl/Library_vclplug_gtk3_kde5.mk b/vcl/Library_vclplug_gtk3_kde5.mk
index dbd5fbf53e88..7ee7f11b088a 100644
--- a/vcl/Library_vclplug_gtk3_kde5.mk
+++ b/vcl/Library_vclplug_gtk3_kde5.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_gtk3_kde5))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_gtk3_kde5,vcl))
+
 # Silence deprecation warnings wholesale as long as vcl/unx/gtk3/*.cxx just
 # forward to vcl/unx/gtk/*.cxx:
 $(eval $(call gb_Library_add_cxxflags,vclplug_gtk3_kde5, \
@@ -59,7 +61,6 @@ $(eval $(call gb_Library_add_libs,vclplug_gtk3_kde5,\
 
 $(eval $(call gb_Library_use_libraries,vclplug_gtk3_kde5,\
     svl \
-    vcl \
     tl \
     utl \
     sot \
diff --git a/vcl/Library_vclplug_gtk4.mk b/vcl/Library_vclplug_gtk4.mk
index 09520c4dba9d..83695a8c1c34 100644
--- a/vcl/Library_vclplug_gtk4.mk
+++ b/vcl/Library_vclplug_gtk4.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_gtk4))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_gtk4,vcl))
+
 # Silence deprecation warnings wholesale as long as vcl/unx/gtk4/*.cxx just
 # forward to vcl/unx/gtk/*.cxx:
 $(eval $(call gb_Library_add_cxxflags,vclplug_gtk4, \
@@ -54,7 +56,6 @@ $(eval $(call gb_Library_add_libs,vclplug_gtk4,\
 ))
 
 $(eval $(call gb_Library_use_libraries,vclplug_gtk4,\
-    vcl \
     svl \
     tl \
     utl \
diff --git a/vcl/Library_vclplug_kf5.mk b/vcl/Library_vclplug_kf5.mk
index bcf8fb6897ad..9e44e5f182fd 100644
--- a/vcl/Library_vclplug_kf5.mk
+++ b/vcl/Library_vclplug_kf5.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_kf5))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_kf5,vcl))
+
 $(eval $(call gb_Library_use_custom_headers,vclplug_kf5,vcl/unx/kf5))
 
 $(eval $(call gb_Library_set_include,vclplug_kf5,\
@@ -35,7 +37,6 @@ $(eval $(call gb_Library_use_sdk_api,vclplug_kf5))
 
 $(eval $(call gb_Library_use_libraries,vclplug_kf5,\
     vclplug_qt5 \
-    vcl \
     tl \
     utl \
     sot \
diff --git a/vcl/Library_vclplug_osx.mk b/vcl/Library_vclplug_osx.mk
index e2a1a5161bdd..230aa020dda0 100644
--- a/vcl/Library_vclplug_osx.mk
+++ b/vcl/Library_vclplug_osx.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_osx))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_osx,vcl))
+
 $(eval $(call gb_Library_set_include,vclplug_osx,\
     $$(INCLUDE) \
     -I$(SRCDIR)/vcl/inc \
@@ -51,7 +53,6 @@ $(eval $(call gb_Library_use_libraries,vclplug_osx,\
     sal \
     salhelper \
     tl \
-    vcl \
 ))
 
 $(eval $(call gb_Library_use_externals,vclplug_osx,\
diff --git a/vcl/Library_vclplug_qt5.mk b/vcl/Library_vclplug_qt5.mk
index 32bf4dc215df..d21f7d989410 100644
--- a/vcl/Library_vclplug_qt5.mk
+++ b/vcl/Library_vclplug_qt5.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_qt5))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_qt5,vcl))
+
 $(eval $(call gb_Library_use_custom_headers,vclplug_qt5,vcl/qt5))
 
 $(eval $(call gb_Library_set_include,vclplug_qt5,\
@@ -36,7 +38,6 @@ $(eval $(call gb_Library_add_defs,vclplug_qt5,\
 $(eval $(call gb_Library_use_sdk_api,vclplug_qt5))
 
 $(eval $(call gb_Library_use_libraries,vclplug_qt5,\
-    vcl \
     tl \
     utl \
     sot \
diff --git a/vcl/Library_vclplug_qt6.mk b/vcl/Library_vclplug_qt6.mk
index 8845da72d604..9a4e627f3e22 100644
--- a/vcl/Library_vclplug_qt6.mk
+++ b/vcl/Library_vclplug_qt6.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_qt6))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_qt6,vcl))
+
 $(eval $(call gb_Library_use_custom_headers,vclplug_qt6,vcl/qt6))
 
 $(eval $(call gb_Library_set_include,vclplug_qt6,\
@@ -35,7 +37,6 @@ $(eval $(call gb_Library_add_defs,vclplug_qt6,\
 $(eval $(call gb_Library_use_sdk_api,vclplug_qt6))
 
 $(eval $(call gb_Library_use_libraries,vclplug_qt6,\
-    vcl \
     tl \
     utl \
     sot \
diff --git a/vcl/Library_vclplug_win.mk b/vcl/Library_vclplug_win.mk
index ca75300670b3..2fd00d7bd03b 100644
--- a/vcl/Library_vclplug_win.mk
+++ b/vcl/Library_vclplug_win.mk
@@ -19,6 +19,8 @@
 
 $(eval $(call gb_Library_Library,vclplug_win))
 
+$(eval $(call gb_Library_set_plugin_for,vclplug_win,vcl))
+
 $(eval $(call gb_Library_set_componentfile,vclplug_win,vcl/vclplug_win))
 
 $(eval $(call gb_Library_set_include,vclplug_win,\
@@ -53,7 +55,6 @@ $(eval $(call gb_Library_use_libraries,vclplug_win,\
     salhelper \
     tl \
     utl \
-    vcl \
 ))
 
 $(eval $(call gb_Library_use_externals,vclplug_win,\