SCons: fix error in linking executables

a long standing error, uncovered recently due to more stringent
checks of the linker on newer platforms, not picking up direct
dependencies of an executable transitively from the linked-to
dynamic libs (which is fine).

The error was to *overwrite* the LIBS construction variable
in the definition of the executable to link, instead of just
adding our dynamic links to the sources to be linked.

SConstruct

@@ -350,7 +350,7 @@ def defineBuildTargets(env, artifacts):
     artifacts['config']  = ( env.ConfigData(env.path.srcConf+'setup.ini', targetDir='$ORIGIN')
                            + env.ConfigData(env.path.srcConf+'dummy_lumiera.ini')
                            )
-    artifacts['lumiera'] = ( env.Program('lumiera', ['src/lumiera/main.cpp'], LIBS=core, install=True)
+    artifacts['lumiera'] = ( env.Program('lumiera', ['src/lumiera/main.cpp'] + core, install=True)
                            + artifacts['config']
                            )
     

src/tool/SConscript

@@ -12,12 +12,12 @@ envSvg.mergeConf(['librsvg-2.0'])
 envSvg.Append(LIBS=support_lib)
 
 
-luidgen =    env.Program('luidgen', 'luidgen.c', LIBS=support_lib, install=True) ## for generating Lumiera-UIDs
+luidgen =    env.Program('luidgen', ['luidgen.c'] + support_lib, install=True)   ## for generating Lumiera-UIDs
 rsvg    = envSvg.Program('rsvg-convert','rsvg-convert.c')                        ## for rendering SVG icons (uses librsvg) 
 
 # build additional test and administrative tools....
 artifacts['tools'] = [ env.Program('hello-world','hello.c', install=True)      #### hello world (checks C build)      
-                     + env.Program('try', 'try.cpp', LIBS=support_lib)         #### to try out some feature...
+                     + env.Program('try', ['try.cpp'] + support_lib)           #### to try out some feature...
                      + luidgen
                      + rsvg
                      ]