Can't compile out of the box on HP-UX

[michael-o]

1. What version of ODPI-C are you using (see dpi.h)?
   5.6.4

2. What OS (and version) is your application on?
   HP-UX 11.31

3. What compiler (and version) did you use?
   HP aCC 06.29

4. What is your version of the Oracle Client (e.g. Instant Client)? How was it installed? Where it is installed?
   Full Oracle Client 19

5. What is your Oracle Database version?
   Oracle 19 SE2

What problem or error(s) you are seeing?

Current Makefile isn't suited for HP aCC because it uses different options compared to GCC/LLVM.

Here is a fix: b020811

Note that is requires #205 solved first.