tool_help.c compilation failure: error: implicit declaration of function ‘strcasecmp’; did you mean ‘strncmp’?

[wyattoday]

I did this

Compile curl using gcc 8.2.1. (using x86 compiler, but it doesn't matter)

I expected the following

Successful build.

curl/libcurl version

7.64.1

operating system

CentOS 6.

The build failed when compiling "tool_help.c":

tool_help.c: In function ‘featcomp’:
tool_help.c:553:10: error: implicit declaration of function ‘strcasecmp’; did you mean ‘strncmp’? [-Werror=implicit-function-declaration]
   return strcasecmp(* (char * const *) p1, * (char * const *) p2);
          ^~~~~~~~~~
          strncmp
cc1: some warnings being treated as errors

Bug was introduced in this PR: #3611

Solution: add #include <strings.h> above the "memdebug.h" include.

[bagder]

Curious that the CI builds nor my own builds get this... ?

[wyattoday]

Maybe your CI servers don't treat that warning as an error (implicit-function-declaration).

The toolset we use is based on the Redhat compilation of the gcc toolset (basically what amounts to devtoolset-8). My guess is they have -Werror=implicit-function-declaration set by default (seeing as they recommend it as a default)