FAQ: 2.5 Install libcurl for both 32bit and 64bit?

docs/FAQ

@@ -30,6 +30,7 @@ FAQ
   2.2 Does curl work/build with other SSL libraries?
   2.3 Where can I find a copy of LIBEAY32.DLL?
   2.4 Does curl support SOCKS (RFC 1928) ?
+  2.5 Install libcurl for both 32bit and 64bit?
 
  3. Usage Problems
   3.1 curl: (1) SSL is disabled, https: not supported
@@ -464,6 +465,32 @@ FAQ
 
   Yes, SOCKS 4 and 5 are supported.
 
+  2.5 Install libcurl for both 32bit and 64bit?
+
+  In curl's configure procedure one of the regular include files get created
+  with platform specific information. The file 'curl/curlbuild.h' in the
+  installed libcurl file tree is therefore somewhat tied to that particular
+  platform.
+
+  To allow applications to get built for either 32bit or 64bit you need to
+  install libcurl headers for both setups and unfortunately curl doesn't do
+  this automatically.
+
+  A commonly used procedure is this:
+
+     $ ./configure [32bit platform]
+     $ mv curl/curlbuild.h curl/curlbuild-32bit.h
+     $ ./configure [64bit platform]
+     $ mv curl/curlbuild.h curl/curlbuild-64bit.h
+
+  Then you make a toplevel curl/curlbuild.h replacement that only does this:
+
+     #ifdef IS_32BIT
+     #include "curlbuild-32bit.h"
+     else
+     #include "curlbuild-64bit.h"
+     #endif
+
 
 3. Usage problems