The last line tells us that gcc failed. gcc is our compiler, so if that fails, we haven't compiled any software, and we need to resolve this issue before moving forward. We saw gcc's fatal error just before that; sql.h: No such file or directory. That tells us that gcc needs a header file somewhere in our buildpath called sql.h. Since it wasn't included in the software we are compiling, we are probably supposed to provide it somehow. This dependency will often be specified by the maintainer/creator of the software, or you might need to ask your pal google.
/root/dd/blks/pyodbc-3.0.6/src/pyodbc.h:48:17: fatal error: sql.h: No such file or directory
error: command 'gcc' failed with exit status 1