Change searched-lib to lib in the Jamfile.

Apparently, searched-lib was not supposed to be used in libraries,
and the simple lib target is the preferred way to declare external
libraries.

bfgroup/b2#431 (comment)

Author: Lastique

build/Jamfile.v2

@@ -12,9 +12,9 @@ import configure ;
 import-search /boost/config/checks ;
 import config : requires ;
 
-searched-lib bcrypt ;
-searched-lib advapi32 ;
-searched-lib coredll ;
+lib bcrypt ;
+lib advapi32 ;
+lib coredll ;
 explicit bcrypt advapi32 coredll ;
 
 # The rule checks if a config macro is defined in the command line or build properties

config/Jamfile.v2

@@ -36,7 +36,7 @@ explicit has_posix_at_apis ;
 obj has_fallocate : has_fallocate.cpp : <include>../src ;
 explicit has_fallocate ;
 
-searched-lib bcrypt ;
+lib bcrypt ;
 explicit bcrypt ;
 
 exe has_bcrypt : has_bcrypt.cpp : <include>../src <library>bcrypt ;