openbabel: prepare for llvm-21

Ref:
#13915 (comment)

Signed-off-by: David Korczynski <[email protected]>

Author: DavidKorczynski

projects/openbabel/build.sh

@@ -15,6 +15,11 @@
 #
 ################################################################################
 
+export CXXFLAGS="${CXXFLAGS} -std=c++17"
+sed -i 's/CMAKE_CXX_STANDARD 11/CMAKE_CXX_STANDARD 17/g' CMakeLists.txt
+
+# Remove use of deprecated functions
+sed -i 's/std::random/\/\/std::random/g' test/*.cpp
 
 # build project
 mkdir build && cd build