don't check for useless __builtin_stack_pointer

It doesn't seem to be supported anyways, and we're not using it too.

CMakeLists.txt

@@ -355,9 +355,6 @@ option(gperftools_emergency_malloc
        "Build emergency malloc"
        ${default_emergency_malloc})
 
-check_c_source_compiles(
-  "int main() { void* sp = __builtin_stack_pointer(); return 0; }"
-  HAVE_BUILTIN_STACK_POINTER)
 check_c_source_compiles(
   "int main() { return __builtin_expect(main != 0, 1); }"
   HAVE_BUILTIN_EXPECT)

cmake/config.h.in

@@ -30,9 +30,6 @@
 /* Define to 1 if you have the <asm/ptrace.h> header file. */
 #cmakedefine HAVE_ASM_PTRACE_H
 
-/* Define to 1 if compiler supports __builtin_stack_pointer */
-#cmakedefine HAVE_BUILTIN_STACK_POINTER
-
 /* Define to 1 if you have the <cygwin/signal.h> header file. */
 #cmakedefine HAVE_CYGWIN_SIGNAL_H
 

configure.ac

@@ -459,14 +459,6 @@ AH_VERBATIM([__STDC_FORMAT_MACROS],
 # define __STDC_FORMAT_MACROS 1
 #endif])
 
-# Check if __builtin_stack_pointer() is available (for elfcore.h)
-AC_MSG_CHECKING([for __builtin_stack_pointer()])
-AC_LINK_IFELSE([AC_LANG_PROGRAM(, [void *sp = __builtin_stack_pointer()])],
-               [AC_DEFINE(HAVE_BUILTIN_STACK_POINTER, 1,
-                      Define to 1 if compiler supports __builtin_stack_pointer)
-                AC_MSG_RESULT([yes])],
-               [AC_MSG_RESULT([no])])
-
 # Check if __environ is available (for GetenvBeforeMain)
 AC_MSG_CHECKING([for __environ])
 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <unistd.h>],

src/windows/config.h

@@ -36,9 +36,6 @@
 /* Define to 1 if you have the <asm/ptrace.h> header file. */
 /* #undef HAVE_ASM_PTRACE_H */
 
-/* Define to 1 if compiler supports __builtin_stack_pointer */
-/* #undef HAVE_BUILTIN_STACK_POINTER */
-
 /* Define to 1 if you have the <cygwin/signal.h> header file. */
 /* #undef HAVE_CYGWIN_SIGNAL_H */