Fix ifdefs around multiline strings and define for AIX machines

Cannot compile original code in AIX, getting following error:

"../../src/network.c", line 1828.1 : 1506-191 (E) The character # is not a valid C source character.
"../../src/network.c", line 1828.3 : 1506-276 (S) Syntax error: possible missing ')'?
"../../src/network.c", line 1828.15: 1506-045 (S) Undeclared identifier SO_BINDTODEVICE.
"../../src/network.c", line 1830.1 : 1506-191 (E) The character # is not a valid C source character.
"../../src/network.c", line 1832.1 : 1506-191 (E) The character # is not a valid C source character.