Trying to compile a load of .c files
(1) The files compile ok, using cc
cc -Wall -Wextra -Wunreachable-code -ggdb -O0 *.c
You are including a binary file in your .cpp source
(line 1 of testme.cpp)
#include "liborientdb-c.a"
Look for a header file named "liborientdb-c.h", and include that (guessing, you probably want to include all of the appropriate *.h header files).
And your makefile should link against the above .a file.
#include "liborientdb-c.a"
.a files are not C source files. Or even text files for that matter.
Usually, the .a files are added on the final link line of the compilation.
cc -o something file.o file2.o liborientdb-c.a etc etc