winbuild: Document CURL_STATICLIB requirement for static libcurl

A static libcurl (ie winbuild mode=static) requires that the user define
CURL_STATICLIB when using it in their application. This is already
covered in the FAQ and INSTALL.md, but is a pretty important point so
now it's noted in the BUILD.WINDOWS.txt as well.

Assisted-by: Michael Vittiglio
Closes https://github.com/curl/curl/pull/4721

diff --git a/winbuild/BUILD.WINDOWS.txt b/winbuild/BUILD.WINDOWS.txt
index 1ede14f01a774d0ad74567ec915c549d3ec5348e..0e88e64490d553c41e0bc09e2df059ebd42f5ccb 100644 (file)
--- a/winbuild/BUILD.WINDOWS.txt
+++ b/winbuild/BUILD.WINDOWS.txt
@@ -114,6 +114,12 @@ already built but not with that option, or if the option was specified
 differently, you must destroy the build directory containing the configuration\r
 so that nmake can build it from scratch.\r
 \r
+Building your own application with a static libcurl\r
+===================================================\r
+When building an application that uses the static libcurl library on Windows,\r
+you must define CURL_STATICLIB. Otherwise the linker will look for dynamic\r
+import symbols.\r
+\r
 Legacy Windows and SSL\r
 ======================\r
 When you build curl using the build files in this directory the default SSL\r