libarchive: Avoid depending on if() to dereference a quoted variable

Utilities/cmlibarchive/CMakeLists.txt

@@ -840,14 +840,14 @@ ENDIF()
 # Check functions
 #
 CMAKE_PUSH_CHECK_STATE()	# Save the state of the variables
-IF ("CMAKE_C_COMPILER_ID" MATCHES "^GNU$")
+IF (CMAKE_C_COMPILER_ID STREQUAL "GNU")
   #
   # During checking functions, we should use -fno-builtin to avoid the
   # failure of function detection which failure is an error "conflicting
   # types for built-in function" caused by using -Werror option.
   #
   SET(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fno-builtin")
-ENDIF ("CMAKE_C_COMPILER_ID" MATCHES "^GNU$")
+ENDIF ()
 CHECK_SYMBOL_EXISTS(_CrtSetReportMode "crtdbg.h" HAVE__CrtSetReportMode)
 CHECK_FUNCTION_EXISTS_GLIBC(chflags HAVE_CHFLAGS)
 CHECK_FUNCTION_EXISTS_GLIBC(chown HAVE_CHOWN)