Test try_compile project mode

The try_compile command project mode builds an entire source tree
instead of one source file.  It uses an existing CMakeLists.txt file in
the given source tree instead of generating one.  This commit creates a
test for the mode in the TryCompile test.

Tests/TryCompile/CMakeLists.txt

@@ -106,6 +106,13 @@ ELSE(CMAKE_ANSI_FOR_SCOPE)
    MESSAGE("Compiler does not support ansi for scope")
 ENDIF(CMAKE_ANSI_FOR_SCOPE)
 
+MESSAGE("Testing try_compile project mode")
+TRY_COMPILE(TEST_INNER
+  ${TryCompile_BINARY_DIR}/CMakeFiles/Inner
+  ${TryCompile_SOURCE_DIR}/Inner
+  TryCompileInner)
+TEST_ASSERT(TEST_INNER "try_compile project mode failed")
+
 ADD_EXECUTABLE(TryCompile pass.c)
 
 ######################################

Tests/TryCompile/Inner/CMakeLists.txt

@@ -0,0 +1,4 @@
+cmake_minimum_required(VERSION 2.6)
+project(TryCompileInner C)
+
+add_executable(inner ../pass.c)