text: // RUN: %clang_cc1 -fsyntax-only -pedantic -verify %s
  // RUN: %clang_cc1 -fsyntax-only -pedantic -verify=system -Wsystem-headers %s
  
  int x;
  
  # 42 // #1
  // expected-warning@#1 {{this style of line directive is a GNU extension}}
  // system-warning@#1 {{this style of line directive is a GNU extension}}
  # 42 "foo" // #2
  // expected-warning@#2 {{this style of line directive is a GNU extension}}
  // system-warning@#2 {{this style of line directive is a GNU extension}}
  # 42 "foo" 2 // #3
  // expected-error@#3 {{invalid line marker flag '2': cannot pop empty include stack}}
  // system-error@#3 {{invalid line marker flag '2': cannot pop empty include stack}}
  # 42 "foo" 1 3  // #4: enter
  // Warnings silenced when -Wsystem-headers isn't passed.
  // system-warning@#4 {{this style of line directive is a GNU extension}}
  # 42 "foo" 2 3  // #5: exit
  // Warnings silenced when -Wsystem-headers isn't passed.
  // system-warning@#5 {{this style of line directive is a GNU extension}}
  # 42 "foo" 2 3 4 // #6
  // expected-error@#6 {{invalid line marker flag '2': cannot pop empty include stack}}
  // system-error@#6 {{invalid line marker flag '2': cannot pop empty include stack}}
  # 42 "foo" 3 4 // #7
  // expected-warning@#7 {{this style of line directive is a GNU extension}}
  // system-warning@#7 {{this style of line directive is a GNU extension}}
  
  
  // Verify that linemarker diddling of the system header flag works.
  
  # 192 "glomp.h" // #8: not a system header.
  // expected-warning@#8 {{this style of line directive is a GNU extension}}
  // system-warning@#8 {{this style of line directive is a GNU extension}}
  
  # 192 "glomp.h" 3 // #9: System header.
  // Warnings silenced when -Wsystem-headers isn't passed.
  // system-warning@#9 {{this style of line directive is a GNU extension}}
  
  #line 42 "blonk.h"  // doesn't change system headerness.
  
  # 97     // #10: doesn't change system headerness.
  // Warnings silenced when -Wsystem-headers isn't passed.
  // system-warning@#10 {{this style of line directive is a GNU extension}}
  
  # 42 "blonk.h"  // #11: DOES change system headerness.
  // Warnings silenced when -Wsystem-headers isn't passed.
  // system-warning@#11 {{this style of line directive is a GNU extension}}
  