Add test environment dependency checks

The test environment is now checked to contain all executables needed for
testing before tests are built. They can be overridden by defining the
relevant HAVE_X variables (currently only HAVE_MYSQLTEST and HAVE_PHP are
defined).

maxscale-system-test/utilities.cmake

@@ -113,3 +113,19 @@ ExternalProject_Add(cdc_connector
 set(CDC_CONNECTOR_INCLUDE ${CMAKE_BINARY_DIR}/cdc_connector/include/ CACHE INTERNAL "")
 set(CDC_CONNECTOR_LIBRARIES ${CMAKE_BINARY_DIR}/cdc_connector/lib/libcdc_connector.so CACHE INTERNAL "")
 include_directories(${CMAKE_BINARY_DIR}/cdc_connector/include)
+
+
+#
+# Check that all required components are present. To build even without them,
+# add e.g. -DHAVE_PHP=Y to the CMake invocation
+#
+
+find_program(HAVE_MYSQLTEST mysqltest)
+if (NOT HAVE_MYSQLTEST)
+  message(FATAL_ERROR "Could not find mysqltest.")
+endif()
+
+find_program(HAVE_PHP php)
+if (NOT HAVE_PHP)
+  message(FATAL_ERROR "Could not find php.")
+endif()