tool_help: Warn if curl and libcurl versions do not match

.. because functionality may be affected if the versions differ.

This commit implements TODO 18.7 "warning if curl version is not in sync
with libcurl version".

Ref: https://github.com/curl/curl/blob/curl-7_64_1/docs/TODO#L1028-L1033

Closes https://github.com/curl/curl/pull/3774

2 files changed, 4 insertions, 8 deletions

diff --git a/docs/TODO b/docs/TODO
index b6a35a777..06cdb980e 100644
--- a/docs/TODO
+++ b/docs/TODO
@@ -150,7 +150,6 @@
  18.4 simultaneous parallel transfers
  18.5 UTF-8 filenames in Content-Disposition
  18.6 warning when setting an option
- 18.7 warning if curl version is not in sync with libcurl version
  18.8 offer color-coded HTTP header output
  18.9 Choose the name of file in braces for complex URLs
  18.10 improve how curl works in a windows console window
@@ -1025,13 +1024,6 @@ that doesn't exist on the server, just like --ftp-create-dirs.
  This can be useful to tell when support for a particular feature hasn't been
  compiled into the library.
 
-18.7 warning if curl version is not in sync with libcurl version
-
- This is usually a sign of a funny, weird or unexpected install situations
- that aren't always quickly nor easily detected by users. curl and libcurl are
- always released in sync and should use the same version numbers unless very
- special situations.
-
 18.8 offer color-coded HTTP header output
 
  By offering different color output on the header name and the header
diff --git a/src/tool_help.c b/src/tool_help.c
index 1ba9975c6..ad6b6a107 100644
--- a/src/tool_help.c
+++ b/src/tool_help.c
@@ -596,6 +596,10 @@ void tool_version_info(void)
       printf(" %s", featp[i]);
     puts(""); /* newline */
   }
+  if(strcmp(CURL_VERSION, curlinfo->version)) {
+    printf("WARNING: curl and libcurl versions do not match. "
+           "Functionality may be affected.\n");
+  }
 }
 
 void tool_list_engines(CURL *curl)