Cannot compile library due to _BSD_SOURCE wrong usage

[TeoGoddet]

Hello,
I'm not a C expert, but I'm having problem compiling when I include open62541 lib (the amalgamated single file)

The error I have is

/mnt/c/Program Files/Dassault Systemes/B426_Cloud/win_b64/resources/Dymola/source/ModelicaInternal.c: In function ‘ModelicaInternal_fullPathName’:
/mnt/c/Program Files/Dassault Systemes/B426_Cloud/win_b64/resources/Dymola/source/ModelicaInternal.c:609:37: error: operator '||' has no left operand

line 609 looks like that in my dymola install :
#if defined(_WIN32) || (_BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || (_POSIX_VERSION >= 200112L))
The concerned line in the actual lib seems this one :

ModelicaStandardLibrary/Modelica/Resources/C-Sources/ModelicaInternal.c

Line 687 in bc5c458

#elif (_BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _POSIX_VERSION >= 200112L)

I think this occur because the _BSD_SOURCE define is empty because of this line in my lib :
https://github.com/open62541/open62541/blob/6115a47125d7e6ccd77488b8572807171adb0602/tools/ua-tool/ua.c#L18

open62541 seems legit to define _BSD_SOURCE empty
see https://ftp.gnu.org/old-gnu/Manuals/glibc-2.2.3/html_node/libc_13.html

I would suggest replacing _BSD_SOURCE by defined(_BSD_SOURCE) in ModelicaInternal.c
I can open a MR is it seem the right fix

Note that there is three occurence of _BSD_SOURCE to fix

[TeoGoddet]

defined(_BSD_SOURCE) resulted in error related "realpath" not existing
I replaced _BSD_SOURCE by 0 and it compiled

[beutlich]

I can open a MR is it seem the right fix

Thanks for reporting. Your PR would be appreciated.

[TeoGoddet]

@beutlich I can open a PR but i'm not confident enough in C and Modelica to be able to say that this fix is legitim
I see you made this commit in 2020, are you able to confirm my intuition ?

[beutlich]

@beutlich I can open a PR but i'm not confident enough in C and Modelica to be able to say that this fix is legitim I see you made this commit in 2020, are you able to confirm my intuition ?

@TeoGoddet I created #4302. If you have a chance to test you can give a review comment there.