cmake: Avoid unnecessary searches for wxWidgets.

Defer the FindwxWidgets include until the CONFIG_ANALYZER
block that actually needs it. Failed searches for wxWidgets
confuse developers unfamiliar with the build system when
trying to use it on new target platforms.

Change-Id: I4e51713cefdf9a6cda1251a91b3bce61ef5cd52e

build/cmake/aom_configure.cmake

diff --git a/build/cmake/aom_configure.cmake b/build/cmake/aom_configure.cmake
index d0c1574..44ecc0b 100644
--- a/build/cmake/aom_configure.cmake
+++ b/build/cmake/aom_configure.cmake
@@ -14,7 +14,6 @@
 include(FindGit)
 include(FindPerl)
 include(FindThreads)
-include(FindwxWidgets)
 
 set(AOM_SUPPORTED_CPU_TARGETS
     "arm64 armv7 armv7s generic mips32 mips64 ppc x86 x86_64")
@@ -157,6 +156,7 @@
 endif ()
 
 if (CONFIG_ANALYZER)
+  include(FindwxWidgets)
   find_package(wxWidgets REQUIRED adv base core)
   include(${wxWidgets_USE_FILE})
 endif ()