Merge branch 'jl/nor-or-nand-and'

Eradicate mistaken use of "nor" (that is, essentially "nor" used
not in "neither A nor B" ;-)) from in-code comments, command output
strings, and documentations.

* jl/nor-or-nand-and:
  code and test: fix misuses of "nor"
  comments: fix misuses of "nor"
  contrib: fix misuses of "nor"
  Documentation: fix misuses of "nor"

http.h

@@ -13,8 +13,7 @@
 /*
  * We detect based on the cURL version if multi-transfer is
  * usable in this implementation and define this symbol accordingly.
- * This is not something Makefile should set nor users should pass
- * via CFLAGS.
+ * This shouldn't be set by the Makefile or by the user (e.g. via CFLAGS).
  */
 #undef USE_CURL_MULTI