(lib)curl.rc: fixup for minor bugs

All resources defined in lib/libcurl.rc and curl.rc are language
neutral.

winbuild/MakefileBuild.vc ALWAYS defines the macro DEBUGBUILD, so the
ifdef's in line 33 of lib/libcurl.rc and src/curl.rc are wrong.

Replace the hard-coded constants in both *.rc files with #define'd
values.

Thumbs-uped-by: Rod Widdowson, Johannes Schindelin
URL: https://curl.haxx.se/mail/lib-2018-11/0000.html
Closes #3348