Modernise CMake #2

This reverts commit cfc69d95afed34e1ba1371df0ddb56f2f491a5cb.
* Change CMAKE_INSTALL_PREFIX default on Windows in order
  to prevent permission denied errors when trying to install
  to "Program Files".
diff --git a/gtests/CMakeLists.txt b/gtests/CMakeLists.txt
index c383ca0..2616ac0 100644
--- a/gtests/CMakeLists.txt
+++ b/gtests/CMakeLists.txt
@@ -1,55 +1,57 @@
-if (TARGET gmock)
-  message(STATUS "Google Mock found - building tests")
+if(BUILD_TESTING)
+    if(TARGET gmock)
+        message(STATUS "Google Mock found - building tests")
 
-  set(TEST_SOURCES
-    # Framework related source files
-    ${CMAKE_CURRENT_SOURCE_DIR}/Initializer.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/main.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Settings.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Settings.h
-    ${CMAKE_CURRENT_SOURCE_DIR}/TestFixture.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/TestFixture.h
+        set(TEST_SOURCES
+            # Framework related source files
+            ${CMAKE_CURRENT_SOURCE_DIR}/Initializer.h
+            ${CMAKE_CURRENT_SOURCE_DIR}/main.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Settings.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Settings.h
+            ${CMAKE_CURRENT_SOURCE_DIR}/TestFixture.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/TestFixture.h
 
-    # Test related source files
-    ${CMAKE_CURRENT_SOURCE_DIR}/AST.FromFile.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/BuiltInResource.FromFile.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Config.FromFile.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/HexFloat.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Hlsl.FromFile.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Link.FromFile.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Link.FromFile.Vk.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Pp.FromFile.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/Spv.FromFile.cpp
-    # -- Remapper tests
-    ${CMAKE_CURRENT_SOURCE_DIR}/Remap.FromFile.cpp
-  )
+            # Test related source files
+            ${CMAKE_CURRENT_SOURCE_DIR}/AST.FromFile.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/BuiltInResource.FromFile.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Config.FromFile.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/HexFloat.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Hlsl.FromFile.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Link.FromFile.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Link.FromFile.Vk.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Pp.FromFile.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/Spv.FromFile.cpp
 
-  add_executable(glslangtests ${TEST_SOURCES})
-  set_property(TARGET glslangtests PROPERTY FOLDER tests)
-  glslang_set_link_args(glslangtests)
-  install(TARGETS glslangtests
-        RUNTIME DESTINATION bin)
+            # -- Remapper tests
+            ${CMAKE_CURRENT_SOURCE_DIR}/Remap.FromFile.cpp)
 
-  set(GLSLANG_TEST_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/../Test")
-  # Supply a default test root directory, so that manual testing
-  # doesn't have to specify the --test-root option in the normal
-  # case that you want to use the tests from the same source tree.
-  target_compile_definitions(glslangtests
-    PRIVATE GLSLANG_TEST_DIRECTORY="${GLSLANG_TEST_DIRECTORY}")
-  target_include_directories(glslangtests PRIVATE
-    ${CMAKE_CURRENT_SOURCE_DIR}
-    ${PROJECT_SOURCE_DIR}
-    ${gmock_SOURCE_DIR}/include
-    ${gtest_SOURCE_DIR}/include)
+        add_executable(glslangtests ${TEST_SOURCES})
+        set_property(TARGET glslangtests PROPERTY FOLDER tests)
+        glslang_set_link_args(glslangtests)
+        install(TARGETS glslangtests
+                RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 
-  set(LIBRARIES
-      SPVRemapper glslang OSDependent OGLCompiler glslang
-      SPIRV glslang-default-resource-limits)
-  if(ENABLE_HLSL)
-    set(LIBRARIES ${LIBRARIES} HLSL)
-  endif(ENABLE_HLSL)
-  target_link_libraries(glslangtests PRIVATE ${LIBRARIES} gmock)
+        set(GLSLANG_TEST_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/../Test")
+        # Supply a default test root directory, so that manual testing
+        # doesn't have to specify the --test-root option in the normal
+        # case that you want to use the tests from the same source tree.
+        target_compile_definitions(glslangtests
+                                   PRIVATE GLSLANG_TEST_DIRECTORY="${GLSLANG_TEST_DIRECTORY}")
+        target_include_directories(glslangtests PRIVATE
+                                   ${CMAKE_CURRENT_SOURCE_DIR}
+                                   ${PROJECT_SOURCE_DIR}
+                                   ${gmock_SOURCE_DIR}/include
+                                   ${gtest_SOURCE_DIR}/include)
 
-  add_test(NAME glslang-gtests
-    COMMAND glslangtests --test-root "${GLSLANG_TEST_DIRECTORY}")
+        set(LIBRARIES
+            SPVRemapper glslang OSDependent OGLCompiler glslang
+            SPIRV glslang-default-resource-limits)
+        if(ENABLE_HLSL)
+            set(LIBRARIES ${LIBRARIES} HLSL)
+        endif(ENABLE_HLSL)
+        target_link_libraries(glslangtests PRIVATE ${LIBRARIES} gmock)
+
+        add_test(NAME glslang-gtests
+                 COMMAND glslangtests --test-root "${GLSLANG_TEST_DIRECTORY}")
+    endif()
 endif()