Allow use of local targets instead of imported ones

To support the LHCb satellite projects use case, I added the option GAUDI_PREFER_LOCAL_TARGETS. When it's set to true, the arguments to the LINK option of gaudi_add_* commands will drop the namespace part of the target if a local target with the same name exist.

So if an already processed subdirectory defines the library MyStuff, the following code

set(GAUDI_PREFER_LOCAL_TARGETS TRUE)
gaudi_add_library(MyOtherStuff SOURCES src/abc.cpp
    LINK PUBLIC SomeProject::MyStuff)

will be equivalent to

set(GAUDI_PREFER_LOCAL_TARGETS TRUE)
gaudi_add_library(MyOtherStuff SOURCES src/abc.cpp
    LINK PUBLIC MyStuff)

The option GAUDI_PREFER_LOCAL_TARGETS is OFF by default.

changed milestone to %v35r2

added lhcb-gaudi-head label

changed the description

mentioned in merge request lhcb-core/LbDevTools!174 (merged)

mentioned in commit lhcb/LHCb@a29991a1

• [2021-03-06 00:05] Validation started with lhcb-gaudi-head#2870
• [2021-03-06 00:53] Validation started with lhcb-run2-gaudi-head#79
• [2021-03-07 00:03] Validation started with lhcb-gaudi-head#2871
• [2021-03-07 00:25] Validation started with lhcb-run2-gaudi-head#80
• [2021-03-07 10:54] Validation started with lhcb-gaudi-head#2872
• [2021-03-08 00:06] Validation started with lhcb-gaudi-head#2873
• [2021-03-08 00:38] Validation started with lhcb-run2-gaudi-head#81
• [2021-03-08 01:10] Validation started with lhcb-run2-gaudi-head#81

approved this merge request

mentioned in commit 0c51539d

merged

mentioned in commit lhcb/LHCb@9abfca51

mentioned in commit lhcb/LHCb@35c26674

mentioned in commit lhcb/LHCb@7d45e0ac

mentioned in commit lhcb/LHCb@44b5e0c0