build: make CURL_FORMAT_CURL_OFF_T[U] work with mingw-w64 <=7.0.0

Add tweak for mingw-w64 when building tests/http/client programs to
avoid a bogus `-Wformat` warning when using mingw-w64 v7.0.0 or older.
The warning is bogus because these programs use curl's `printf()`
implementation that is guaranteed to support that format spec.

Add this for both CMake and autotools. (But only CMake is CI tested with
an old toolchain.)

Apply the workaround to `docs/examples`, and fix an example to use
curl's `printf()` with `CURL_FORMAT_CURL_OFF_T`.

Reintroduce curl `printf()` calls into `tests/http/client`, via #14625.
Also restore large number masks to a printf, changed earlier in #14382.

Follow-up to 232302f88a #14382
Ref: https://github.com/curl/curl/pull/14625#issuecomment-2302361737

Closes #14640

docs/examples/CMakeLists.txt

@@ -34,6 +34,10 @@ foreach(_example IN LISTS check_PROGRAMS)
   if(LIB_SELECTED STREQUAL LIB_STATIC AND WIN32)
     set_property(TARGET ${_example_target} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_STATICLIB")
   endif()
+  if(MINGW)
+    # For mingw-w64 7.0.0 and earlier to avoid '-Wformat='
+    set_property(TARGET ${_example_target} APPEND PROPERTY COMPILE_DEFINITIONS "__USE_MINGW_ANSI_STDIO=1")
+  endif()
   set_target_properties(${_example_target} PROPERTIES
     OUTPUT_NAME "${_example}" UNITY_BUILD OFF)
 endforeach()

docs/examples/Makefile.am

@@ -46,6 +46,11 @@ if USE_CPPFLAG_CURL_STATICLIB
 AM_CPPFLAGS += -DCURL_STATICLIB
 endif
 
+if HAVE_MINGW
+# For mingw-w64 7.0.0 and earlier to avoid '-Wformat='
+AM_CPPFLAGS += -D__USE_MINGW_ANSI_STDIO=1
+endif
+
 # Prevent LIBS from being used for all link targets
 LIBS = $(BLANK_AT_MAKETIME)
 

docs/examples/ftpgetinfo.c

@@ -75,8 +75,8 @@ int main(void)
       res = curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD_T,
                               &filesize);
       if((CURLE_OK == res) && (filesize>0))
-        printf("filesize %s: %" CURL_FORMAT_CURL_OFF_T " bytes\n",
-               filename, filesize);
+        curl_mprintf("filesize %s: %" CURL_FORMAT_CURL_OFF_T " bytes\n",
+                     filename, filesize);
     }
     else {
       /* we failed */