Stop caching variables when we find its not the library we're looking…

… for

CMake/HPHPFindLibs.cmake

@@ -42,13 +42,13 @@ set(CMAKE_REQUIRED_LIBRARIES "${LIBEVENT_LIB}")
 CHECK_FUNCTION_EXISTS("evhttp_bind_socket_with_fd" HAVE_CUSTOM_LIBEVENT)
 if (NOT HAVE_CUSTOM_LIBEVENT)
 	message(SEND_ERROR "Custom libevent is required with HipHop patches")
+	unset(HAVE_CUSTOM_LIBEVENT CACHE)
+	unset(LIBEVENT_INCLUDE_DIR CACHE)
+	unset(LIBEVENT_LIB CACHE)
+	unset(LibEvent_FOUND CACHE)
 endif ()
 set(CMAKE_REQUIRED_LIBRARIES)
 
-# libafdt checks
-#find_package(LibAfdt REQUIRED)
-#include_directories(${LibAfdt_INCLUDE_DIR})
-
 # GD checks
 find_package(GD REQUIRED)
 
@@ -76,6 +76,10 @@ set(CMAKE_REQUIRED_LIBRARIES "${CURL_LIBRARIES}")
 CHECK_FUNCTION_EXISTS("curl_multi_select" HAVE_CUSTOM_CURL)
 if (NOT HAVE_CUSTOM_CURL)
         message(SEND_ERROR "Custom libcurl is required with HipHop patches ${HAVE_CUSTOM_CURL}")
+		unset(HAVE_CUSTOM_CURL CACHE)
+		unset(CURL_INCLUDE_DIR CACHE)
+		unset(CURL_LIBRARIES CACHE)
+		unset(CURL_FOUND CACHE)
 endif ()
 set(CMAKE_REQUIRED_LIBRARIES)
 
@@ -99,6 +103,9 @@ find_package(ICU REQUIRED)
 if (ICU_FOUND)
 	if (ICU_VERSION VERSION_LESS "4.2")
 		message(SEND_ERROR "ICU is too old, found ${ICU_VERSION} and we need 4.2")
+		unset(ICU_FOUND CACHE)
+		unset(ICU_INCLUDE_DIRS CACHE)
+		unset(ICU_LIBRARIES CACHE)
 	endif (ICU_VERSION VERSION_LESS "4.2")
 	include_directories(${ICU_INCLUDE_DIRS})
 endif (ICU_FOUND)