diff --git a/Modules/CheckPrototypeDefinition.cmake b/Modules/CheckPrototypeDefinition.cmake
index dfa54d8ec..e203d4c3f 100644
--- a/Modules/CheckPrototypeDefinition.cmake
+++ b/Modules/CheckPrototypeDefinition.cmake
@@ -57,7 +57,7 @@ get_filename_component(__check_proto_def_dir "${CMAKE_CURRENT_LIST_FILE}" PATH)
 
 function(CHECK_PROTOTYPE_DEFINITION _FUNCTION _PROTOTYPE _RETURN _HEADER _VARIABLE)
 
-  if ("${_VARIABLE}" MATCHES "^${_VARIABLE}$")
+  if (NOT DEFINED ${_VARIABLE})
     set(CHECK_PROTOTYPE_DEFINITION_CONTENT "/* */\n")
 
     set(CHECK_PROTOTYPE_DEFINITION_FLAGS ${CMAKE_REQUIRED_FLAGS})
diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index 9a784847d..d6a6b7275 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -240,7 +240,7 @@ function(_ep_parse_arguments f name ns args)
     set(is_value 1)
 
     if(arg MATCHES "^[A-Z][A-Z0-9_][A-Z0-9_]+$" AND
-        NOT ((arg STREQUAL "${key}") AND (key STREQUAL "COMMAND")) AND
+        NOT (("x${arg}x" STREQUAL "x${key}x") AND ("x${key}x" STREQUAL "xCOMMANDx")) AND
         NOT arg MATCHES "^(TRUE|FALSE)$")
       if(_ep_keywords_${f} AND arg MATCHES "${_ep_keywords_${f}}")
         set(is_value 0)
diff --git a/Tests/CMakeOnly/MajorVersionSelection/CMakeLists.txt b/Tests/CMakeOnly/MajorVersionSelection/CMakeLists.txt
index 74f54514e..2511064a2 100644
--- a/Tests/CMakeOnly/MajorVersionSelection/CMakeLists.txt
+++ b/Tests/CMakeOnly/MajorVersionSelection/CMakeLists.txt
@@ -20,13 +20,13 @@ endif ()
 
 string(TOUPPER "${MAJOR_TEST_MODULE}" MODULE_UPPER)
 
-if ( ( ${MAJOR_TEST_MODULE}_FOUND OR ${MODULE_UPPER}_FOUND ) AND "${VERSION_VAR}")
+if ( ( ${MAJOR_TEST_MODULE}_FOUND OR ${MODULE_UPPER}_FOUND ) AND ${VERSION_VAR})
   message(STATUS "${VERSION_VAR} is '${${VERSION_VAR}}'")
-  if ("${VERSION_VAR}" VERSION_LESS MAJOR_TEST_VERSION)
+  if (${VERSION_VAR} VERSION_LESS MAJOR_TEST_VERSION)
     message(SEND_ERROR "Found version ${${VERSION_VAR}} is less than requested major version ${MAJOR_TEST_VERSION}")
   endif ()
   math(EXPR V_PLUS_ONE "${MAJOR_TEST_VERSION} + 1")
-  if ("${VERSION_VAR}" VERSION_GREATER V_PLUS_ONE)
+  if (${VERSION_VAR} VERSION_GREATER V_PLUS_ONE)
     message(SEND_ERROR "Found version ${${VERSION_VAR}} is greater than requested major version ${MAJOR_TEST_VERSION}")
   endif ()
 endif ()
diff --git a/Tests/FunctionTest/CMakeLists.txt b/Tests/FunctionTest/CMakeLists.txt
index d1fada495..68da972c6 100644
--- a/Tests/FunctionTest/CMakeLists.txt
+++ b/Tests/FunctionTest/CMakeLists.txt
@@ -92,7 +92,7 @@ endfunction()
 
 STRANGE_FUNCTION(var)
 set(second_var "second_var")
-if("${var}" STREQUAL "strange_function" AND "${second_var}" STREQUAL "second_var")
+if("x${var}" STREQUAL "xstrange_function" AND "x${second_var}" STREQUAL "xsecond_var")
   PASS("Case Test" "(${var} ${second_var})")
 else()
   FAILED("Case test" "(${var} ${second_var})")
diff --git a/Tests/MacroTest/CMakeLists.txt b/Tests/MacroTest/CMakeLists.txt
index 02bb31f20..6c6dfb625 100644
--- a/Tests/MacroTest/CMakeLists.txt
+++ b/Tests/MacroTest/CMakeLists.txt
@@ -36,7 +36,7 @@ macro(strange_macro m)
 endmacro()
 STRANGE_MACRO(var)
 set(second_var "second_var")
-if("${var}" STREQUAL "strange_macro" AND "${second_var}" STREQUAL "second_var")
+if("x${var}" STREQUAL "xstrange_macro" AND "x${second_var}" STREQUAL "xsecond_var")
   PASS("Case Test" "(${var} ${second_var})")
 else()
   FAILED("Case test" "(${var} ${second_var})")
diff --git a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_NO_PKGCONFIG_PATH.cmake b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_NO_PKGCONFIG_PATH.cmake
index 924976efa..89ce4c6d8 100644
--- a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_NO_PKGCONFIG_PATH.cmake
+++ b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_NO_PKGCONFIG_PATH.cmake
@@ -26,7 +26,7 @@ endif()
 
 pkg_check_modules(FOO "${expected_path}")
 
-if(NOT "FOO_FOUND")
+if(NOT FOO_FOUND)
   message(FATAL_ERROR "Expected PKG_CONFIG_PATH: \"${expected_path}\".")
 endif()
 
@@ -36,6 +36,6 @@ set(PKG_CONFIG_USE_CMAKE_PREFIX_PATH TRUE)
 
 pkg_check_modules(BAR "${expected_path}" NO_CMAKE_PATH NO_CMAKE_ENVIRONMENT_PATH)
 
-if(NOT "BAR_FOUND")
+if(NOT BAR_FOUND)
   message(FATAL_ERROR "Expected PKG_CONFIG_PATH: \"${expected_path}\".")
 endif()
diff --git a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH.cmake b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH.cmake
index 4a66e8506..c90327955 100644
--- a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH.cmake
+++ b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH.cmake
@@ -46,6 +46,6 @@ endif()
 
 pkg_check_modules(FOO "${expected_path}")
 
-if(NOT "FOO_FOUND")
+if(NOT FOO_FOUND)
   message(FATAL_ERROR "Expected PKG_CONFIG_PATH: \"${expected_path}\".")
 endif()
diff --git a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_ENVIRONMENT_PATH.cmake b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_ENVIRONMENT_PATH.cmake
index 0b057b8d7..a52bcbf81 100644
--- a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_ENVIRONMENT_PATH.cmake
+++ b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_ENVIRONMENT_PATH.cmake
@@ -46,6 +46,6 @@ endif()
 
 pkg_check_modules(FOO "${expected_path}" NO_CMAKE_ENVIRONMENT_PATH)
 
-if(NOT "FOO_FOUND")
+if(NOT FOO_FOUND)
   message(FATAL_ERROR "Expected PKG_CONFIG_PATH: \"${expected_path}\".")
 endif()
diff --git a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_PATH.cmake b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_PATH.cmake
index a3154f13d..2fabe5b43 100644
--- a/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_PATH.cmake
+++ b/Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_PATH.cmake
@@ -46,6 +46,6 @@ endif()
 
 pkg_check_modules(FOO "${expected_path}" NO_CMAKE_PATH)
 
-if(NOT "FOO_FOUND")
+if(NOT FOO_FOUND)
   message(FATAL_ERROR "Expected PKG_CONFIG_PATH: \"${expected_path}\".")
 endif()
diff --git a/Tests/StringFileTest/CMakeLists.txt b/Tests/StringFileTest/CMakeLists.txt
index 683f96945..e6c61522d 100644
--- a/Tests/StringFileTest/CMakeLists.txt
+++ b/Tests/StringFileTest/CMakeLists.txt
@@ -123,7 +123,7 @@ string(STRIP "ST2 " ST2)
 string(STRIP "  ST3" ST3)
 
 foreach(var ST1 ST2 ST3)
-  if("${var}" STREQUAL "${${var}}")
+  if("x${var}" STREQUAL "x${${var}}")
     message("[${var}] == [${${var}}]")
   else()
     message(SEND_ERROR "Problem with the STRIP command for ${var}: [${${var}}]")