Removal of CURLOPT_OBSOLETE72 causes downstream breakage

[dg0yt]

Noticed in vpckg CI run on CURL HEAD:

CURLOPT_OBSOLETE72 is still used in the header for

curl/include/curl/curl.h

Line 723 in 3fc81be

#define CURLOPT_CLOSEPOLICY CURLOPT_OBSOLETE72

and CURLOPT_CLOSEPOLICY is used downstream in curlpp and curlcpp. (Edit: The problem really seems to be limited to these two C++ wrappers.)

Originally posted by @dg0yt in #14634 (comment)

[dg0yt]

e.g. curlpp:

FAILED: CMakeFiles/curlpp.dir/src/curlpp/Options.cpp.o 
/usr/bin/c++ -DCURL_STATICLIB -I/mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include -isystem /mnt/vcpkg-ci/installed/x64-linux/include -fPIC -g -std=c++11 -MD -MT CMakeFiles/curlpp.dir/src/curlpp/Options.cpp.o -MF CMakeFiles/curlpp.dir/src/curlpp/Options.cpp.o.d -o CMakeFiles/curlpp.dir/src/curlpp/Options.cpp.o -c /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/src/curlpp/Options.cpp
In file included from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/internal/SList.hpp:29,
                 from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/internal/OptionContainerType.hpp:28,
                 from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/internal/OptionContainer.hpp:28,
                 from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/Option.hpp:28,
                 from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/Options.hpp:28,
                 from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/src/curlpp/Options.cpp:25:
/mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/Options.hpp:281:55: error: ‘CURLOPT_OBSOLETE72’ was not declared in this scope; did you mean ‘CURLFORM_OBSOLETE2’?
  281 |         typedef curlpp::OptionTrait<curl_closepolicy, CURLOPT_CLOSEPOLICY> ClosePolicy;
      |                                                       ^~~~~~~~~~~~~~~~~~~
In file included from /mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/src/curlpp/Options.cpp:25:
/mnt/vcpkg-ci/b/curlpp/src/95a4f05eb9-7d2abb29f5.clean/include/curlpp/Options.hpp:281:74: error: template argument 2 is invalid
  281 |         typedef curlpp::OptionTrait<curl_closepolicy, CURLOPT_CLOSEPOLICY> ClosePolicy;
      |                                                                          ^

[dg0yt]

This fixed local builds:

diff --git a/include/curl/curl.h b/include/curl/curl.h
index 1609ff6..d39d978 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -1351,7 +1351,9 @@ typedef enum {
   /* Max amount of cached alive connections */
   CURLOPT(CURLOPT_MAXCONNECTS, CURLOPTTYPE_LONG, 71),
 
-  /* 72 = OBSOLETE */
+  /* OBSOLETE, do not use! */
+  CURLOPT(CURLOPT_OBSOLETE72, CURLOPTTYPE_LONG, 72),
+
   /* 73 = OBSOLETE */
 
   /* Set to explicitly use a new connection for the upcoming transfer.

CI run later.

[bagder]

I propose a slightly different fix.

But also: I would urge you to fix those projects. Those symbols have been deprecated for over 17 years.

[dg0yt]

Still an issue for the C++ wrappers: #14748 (comment)