Dependency on build libaries while building an IOC

[eddybl]

Describe the bug

Building an IOC against the OPC-UA module requires the presence of libxml2-dev module (probably the same with the ssl libs), although this should only be needed to build the OPC-UA module itself

To Reproduce
Steps to reproduce the behavior:

1. Setup server without libxml2-dev, but installed OPC-UA module
2. Try to build an IOC with OPC-UA support
3. See build error

Expected behavior
It should build without libxml2-dev

Build Log

[...]
make -C O.linux-x86_64 -f ../Makefile TOP=../../.. \
    T_A=linux-x86_64 install
make[3]: Entering directory '/home/ws/hi0724/iocs/magnets/magnetsApp/src/O.linux-x86_64'
/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE          -D_X86_64_ -DUNIX  -Dlinux      -O3 -g   -Wall      -mtune=generic     -m64  -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include      -I/opt/epics/modules/opcua-0.10.0/include -I/opt/epics/base-7.0.9/include/compiler/gcc -I/opt/epics/base-7.0.9/include/os/Linux -I/opt/epics/base-7.0.9/include        -MM -MF magnetsMain.d  ../magnetsMain.cpp
Creating dbd file magnets.dbd
perl -CSD /opt/epics/base-7.0.9/bin/linux-x86_64/dbdExpand.pl   -I. -I.. -I../O.Common -I../../../dbd -I/opt/epics/modules/opcua-0.10.0/dbd -I/opt/epics/base-7.0.9/dbd -o magnets.dbd base.dbd opcua.dbd
perl -CSD /opt/epics/base-7.0.9/bin/linux-x86_64/registerRecordDeviceDriver.pl   -I. -I.. -I../O.Common -I../../../dbd -I/opt/epics/modules/opcua-0.10.0/dbd -I/opt/epics/base-7.0.9/dbd    -o magnets_registerRecordDeviceDriver.cpp \
            ../O.Common/magnets.dbd magnets_registerRecordDeviceDriver /home/ws/hi0724/iocs/magnets
/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE          -D_X86_64_ -DUNIX  -Dlinux      -O3 -g   -Wall      -mtune=generic     -m64  -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include      -I/opt/epics/modules/opcua-0.10.0/include -I/opt/epics/base-7.0.9/include/compiler/gcc -I/opt/epics/base-7.0.9/include/os/Linux -I/opt/epics/base-7.0.9/include        -MM -MF magnets_registerRecordDeviceDriver.d  magnets_registerRecordDeviceDriver.cpp
Installing created dbd file ../../../dbd/magnets.dbd
mkdir ../../../dbd
/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE          -D_X86_64_ -DUNIX  -Dlinux      -O3 -g   -Wall      -mtune=generic     -m64  -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include      -I/opt/epics/modules/opcua-0.10.0/include -I/opt/epics/base-7.0.9/include/compiler/gcc -I/opt/epics/base-7.0.9/include/os/Linux -I/opt/epics/base-7.0.9/include        -c magnets_registerRecordDeviceDriver.cpp
/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE          -D_X86_64_ -DUNIX  -Dlinux      -O3 -g   -Wall      -mtune=generic     -m64  -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include      -I/opt/epics/modules/opcua-0.10.0/include -I/opt/epics/base-7.0.9/include/compiler/gcc -I/opt/epics/base-7.0.9/include/os/Linux -I/opt/epics/base-7.0.9/include        -c ../magnetsMain.cpp
/usr/bin/g++ -o magnets  -L/home/ws/hi0724/iocs/magnets/lib/linux-x86_64 -L/opt/epics/base-7.0.9/lib/linux-x86_64 -L/opt/epics/modules/opcua-0.10.0/lib/linux-x86_64 -Wl,-rpath,/home/ws/hi0724/iocs/magnets/lib/linux-x86_64 -Wl,-rpath,/opt/epics/base-7.0.9/lib/linux-x86_64 -Wl,-rpath,/opt/epics/modules/opcua-0.10.0/lib/linux-x86_64          -rdynamic -m64         magnets_registerRecordDeviceDriver.o magnetsMain.o    -lopcua -ldbRecStd -ldbCore -lca -lCom  -lcrypto -lxml2 
/usr/bin/ld: cannot find -lxml2: No such file or directory
collect2: error: ld returned 1 exit status
make[3]: *** [/opt/epics/base-7.0.9/configure/RULES_BUILD:232: magnets] Error 1
make[3]: Leaving directory '/home/ws/hi0724/iocs/magnets/magnetsApp/src/O.linux-x86_64'
make[2]: *** [/opt/epics/base-7.0.9/configure/RULES_ARCHS:58: install.linux-x86_64] Error 2
make[2]: Leaving directory '/home/ws/hi0724/iocs/magnets/magnetsApp/src'
make[1]: *** [/opt/epics/base-7.0.9/configure/RULES_DIRS:85: src.install] Error 2
make[1]: Leaving directory '/home/ws/hi0724/iocs/magnets/magnetsApp'
make: *** [/opt/epics/base-7.0.9/configure/RULES_DIRS:85: magnetsApp.install] Error 2

Setup (please complete the following information if applicable):

• OPCUA Support: 0.10.0
• Platform: Ubuntu 24.04
• EPICS Base: 7.0.9
• Client library: open62541

Additional context
A "quick" work around is:

• Rename the modules/opcua-0.10.0/cfg folder to cfg.removed and then the IOC builds

[ralphlange]

In a setup using shared libraries, the shared libraries for libxml2 and libssl are still needed on the system, as they are dependencies of the Device Support module.
You shouldn't need the -dev packages, containing static libraries and header files, though.

Oh, I see, -lcrypto and -lxml2 on the IOC link line require .so files, and these are indeed soft links in the -dev packages. Maybe these two need to be removed from the linker line?

[eddybl]

Oh, I see, -lcrypto and -lxml2 on the IOC link line require .so files, and these are indeed soft links in the -dev packages. Maybe these two need to be removed from the linker line?

Yeah, I guess so? The non -dev packages are probably quite hard not to have installed anyway

[ralphlange]

I'll have a PR for you to try - stay tuned...