Eeschema: build with object libraries

This is done to allow access to the eeschema library
internals for purposes of test and script access, as the
DLL library has highly restrictive -fvisibility settings
that otherwise prevent the tests being able to access 99.9%
of the eeschema library functions (only a single function
is APIEXPORT'ed, therefore that's the only test we can do).

Using object libraries is a bit of a hack, and makes for
a slower link when done for multiple targets, but with the currently
supported CMake versions, it's about as good as we can get.

A better solution in the longer term may be to break eeschema_kiface(_objects)
into many smaller libraries, each of which has a much more defined scope,
rather than one big interlinked amorphous lump. This has the advantage that
each module is testable in isolation, and we get better organisation of
inter-dependencies in the codebase.

Then, the kiface DLL will gather these sub-libs and present what
is needed on the visible DLL API. Thus, we get both a testable
suite of library functions, and a restricted kiface DLL interface.

eeschema/CMakeLists.txt

@@ -145,7 +145,6 @@ set( EESCHEMA_SRCS
     edit_bitmap.cpp
     edit_component_in_schematic.cpp
     edit_label.cpp
-    eeschema.cpp
     eeschema_config.cpp
     erc.cpp
     fields_grid_table.cpp
@@ -332,21 +331,30 @@ target_link_libraries( eeschema
     ${wxWidgets_LIBRARIES}
     )
 
-# the DSO (KIFACE) housing the main eeschema code:
-add_library( eeschema_kiface SHARED
+# the main Eeschema program, in DSO form.
+add_library( eeschema_kiface_objects OBJECT
     ${EESCHEMA_SRCS}
     ${EESCHEMA_COMMON_SRCS}
     )
+
+# CMake <3.9 can't link anything to object libraries,
+# but we only need include directories, as we will link the kiface MODULE
+target_include_directories( eeschema_kiface_objects PRIVATE
+   $<TARGET_PROPERTY:common,INCLUDE_DIRECTORIES>
+   $<TARGET_PROPERTY:legacy_gal,INCLUDE_DIRECTORIES>
+)
+
+add_library( eeschema_kiface MODULE
+    eeschema.cpp
+    $<TARGET_OBJECTS:eeschema_kiface_objects>
+    )
+
 target_link_libraries( eeschema_kiface
-    gal
     legacy_gal
     common
     ${wxWidgets_LIBRARIES}
     ${GDI_PLUS_LIBRARIES}
     )
-target_include_directories( eeschema_kiface PUBLIC
-    ${CMAKE_CURRENT_SOURCE_DIR}
-    )
 
 if( KICAD_SPICE )
     target_link_libraries( eeschema_kiface

qa/eeschema/CMakeLists.txt

@@ -23,17 +23,11 @@
 
 
 include_directories( BEFORE ${INC_BEFORE} )
-include_directories( AFTER ${INC_AFTER} )
-
 
 add_executable( qa_eeschema
     # A single top to load the pcnew kiface
     # ../../common/single_top.cpp
 
-    # stuff from common due to...units?
-    ../../common/base_units.cpp
-    ../../common/eda_text.cpp
-
     # stuff from common which is needed...why?
     ../../common/colors.cpp
     ../../common/observable.cpp
@@ -44,18 +38,28 @@ add_executable( qa_eeschema
     test_module.cpp
 
     test_eagle_plugin.cpp
+
+    # Older CMakes cannot link OBJECT libraries
+    # https://cmake.org/pipermail/cmake/2013-November/056263.html
+    $<TARGET_OBJECTS:eeschema_kiface_objects>
 )
 
 target_link_libraries( qa_eeschema
-    eeschema_kiface
     common
-    gal
+    legacy_gal
     qa_utils
     unit_test_utils
     ${GDI_PLUS_LIBRARIES}
     ${Boost_LIBRARIES}
 )
 
+target_include_directories( qa_eeschema PUBLIC
+    # Paths for eeschema lib usage (should really be in eeschema/common
+    # target_include_directories and made PUBLIC)
+    ${CMAKE_SOURCE_DIR}/eeschema
+    ${INC_AFTER}
+)
+
 # Eeschema tests, so pretend to be eeschema (for units, etc)
 target_compile_definitions( qa_eeschema
     PUBLIC EESCHEMA