Issue #7117 (backport py3k float repr) continued:

 - add double endianness detection to configure script
 - add configure-time check to see whether we can use inline
   assembly to get and set x87 control word in configure script
 - add functions to get and set x87 control word in Python/pymath.c
 - add pyport.h logic to determine whether it's safe to use the
   short float repr or not

Include/pymacconfig.h

@@ -17,6 +17,9 @@
 # undef SIZEOF_VOID_P
 # undef SIZEOF__BOOL
 # undef WORDS_BIGENDIAN
+# undef DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754
+# undef DOUBLE_IS_BIG_ENDIAN_IEEE754
+# undef DOUBLE_IS_LITTLE_ENDIAN_IEEE754
 
 #    undef VA_LIST_IS_ARRAY
 #    if defined(__LP64__) && defined(__x86_64__)
@@ -65,6 +68,9 @@
 
 #ifdef __BIG_ENDIAN__
 #define WORDS_BIGENDIAN 1
+#define DOUBLE_IS_BIG_ENDIAN_IEEE754
+#else
+#define DOUBLE_IS_LITTLE_ENDIAN_IEEE754
 #endif /* __BIG_ENDIAN */
 
 	/* 

Include/pymath.h

@@ -92,6 +92,11 @@ PyAPI_FUNC(double) _Py_force_double(double);
 #  endif
 #endif
 
+#ifdef HAVE_GCC_ASM_FOR_X87
+PyAPI_FUNC(unsigned short) _Py_get_387controlword(void);
+PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
+#endif
+
 /* Py_IS_NAN(X)
  * Return 1 if float or double arg is a NaN, else 0.
  * Caution:

Include/pyport.h

@@ -488,6 +488,80 @@ extern "C" {
 			errno = 0;					\
 	} while(0)
 
+/*  The functions _Py_dg_strtod and _Py_dg_dtoa in Python/dtoa.c (which are
+ *  required to support the short float repr introduced in Python 3.1) require
+ *  that the floating-point unit that's being used for arithmetic operations
+ *  on C doubles is set to use 53-bit precision.  It also requires that the
+ *  FPU rounding mode is round-half-to-even, but that's less often an issue.
+ *
+ *  If your FPU isn't already set to 53-bit precision/round-half-to-even, and
+ *  you want to make use of _Py_dg_strtod and _Py_dg_dtoa, then you should
+ *
+ *     #define HAVE_PY_SET_53BIT_PRECISION 1
+ *
+ *  and also give appropriate definitions for the following three macros:
+ *
+ *    _PY_SET_53BIT_PRECISION_START : store original FPU settings, and
+ *        set FPU to 53-bit precision/round-half-to-even
+ *    _PY_SET_53BIT_PRECISION_END : restore original FPU settings
+ *    _PY_SET_53BIT_PRECISION_HEADER : any variable declarations needed to
+ *        use the two macros above.
+ *
+ * The macros are designed to be used within a single C function: see
+ * Python/pystrtod.c for an example of their use.
+ */
+
+/* get and set x87 control word for gcc/x86 */
+#ifdef HAVE_GCC_ASM_FOR_X87
+#define HAVE_PY_SET_53BIT_PRECISION 1
+/* _Py_get/set_387controlword functions are defined in Python/pymath.c */
+#define _Py_SET_53BIT_PRECISION_HEADER				\
+	unsigned short old_387controlword, new_387controlword
+#define _Py_SET_53BIT_PRECISION_START					\
+	do {								\
+		old_387controlword = _Py_get_387controlword();		\
+		new_387controlword = (old_387controlword & ~0x0f00) | 0x0200; \
+		if (new_387controlword != old_387controlword)		\
+			_Py_set_387controlword(new_387controlword);	\
+	} while (0)
+#define _Py_SET_53BIT_PRECISION_END				\
+	if (new_387controlword != old_387controlword)		\
+		_Py_set_387controlword(old_387controlword)
+#endif
+
+/* default definitions are empty */
+#ifndef HAVE_PY_SET_53BIT_PRECISION
+#define _Py_SET_53BIT_PRECISION_HEADER
+#define _Py_SET_53BIT_PRECISION_START
+#define _Py_SET_53BIT_PRECISION_END
+#endif
+
+/* If we can't guarantee 53-bit precision, don't use the code
+   in Python/dtoa.c, but fall back to standard code.  This
+   means that repr of a float will be long (17 sig digits).
+
+   Realistically, there are two things that could go wrong:
+
+   (1) doubles aren't IEEE 754 doubles, or
+   (2) we're on x86 with the rounding precision set to 64-bits
+       (extended precision), and we don't know how to change
+       the rounding precision.
+ */
+
+#if !defined(DOUBLE_IS_LITTLE_ENDIAN_IEEE754) && \
+    !defined(DOUBLE_IS_BIG_ENDIAN_IEEE754) && \
+    !defined(DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754)
+#define PY_NO_SHORT_FLOAT_REPR
+#endif
+
+/* double rounding is symptomatic of use of extended precision on x86.  If
+   we're seeing double rounding, and we don't have any mechanism available for
+   changing the FPU rounding precision, then don't use Python/dtoa.c. */
+#if defined(X87_DOUBLE_ROUNDING) && !defined(HAVE_PY_SET_53BIT_PRECISION)
+#define PY_NO_SHORT_FLOAT_REPR
+#endif
+
+
 /* Py_DEPRECATED(version)
  * Declare a variable, type, or function deprecated.
  * Usage:

PC/pyconfig.h

@@ -749,4 +749,8 @@ Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
    socket handles greater than FD_SETSIZE */
 #define Py_SOCKET_FD_CAN_BE_GE_FD_SETSIZE
 
+/* Define if C doubles are 64-bit IEEE 754 binary format, stored with the
+   least significant byte first */
+#define DOUBLE_IS_LITTLE_ENDIAN_IEEE754 1
+
 #endif /* !Py_CONFIG_H */

Python/pymath.c

@@ -13,6 +13,24 @@ double _Py_force_double(double x)
 }
 #endif
 
+#ifdef HAVE_GCC_ASM_FOR_X87
+
+/* inline assembly for getting and setting the 387 FPU control word on
+   gcc/x86 */
+
+unsigned short _Py_get_387controlword(void) {
+    unsigned short cw;
+    __asm__ __volatile__ ("fnstcw %0" : "=m" (cw));
+    return cw;
+}
+
+void _Py_set_387controlword(unsigned short cw) {
+    __asm__ __volatile__ ("fldcw %0" : : "m" (cw));
+}
+
+#endif
+
+
 #ifndef HAVE_HYPOT
 double hypot(double x, double y)
 {

configure

 #! /bin/sh
-# From configure.in Revision: 74978 .
+# From configure.in Revision: 75131 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for python 2.7.
 #
@@ -23233,12 +23233,298 @@ echo "${ECHO_T}default LIBC=\"$LIBC\"" >&6; }
 fi
 
 
-# ************************************
-# * Check for mathematical functions *
-# ************************************
+# **************************************************
+# * Check for various properties of floating point *
+# **************************************************
 
-LIBS_SAVE=$LIBS
-LIBS="$LIBS $LIBM"
+{ echo "$as_me:$LINENO: checking whether C doubles are little-endian IEEE 754 binary64" >&5
+echo $ECHO_N "checking whether C doubles are little-endian IEEE 754 binary64... $ECHO_C" >&6; }
+if test "${ac_cv_little_endian_double+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+
+if test "$cross_compiling" = yes; then
+  ac_cv_little_endian_double=no
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <string.h>
+int main() {
+    double x = 9006104071832581.0;
+    if (memcmp(&x, "\x05\x04\x03\x02\x01\xff\x3f\x43", 8) == 0)
+        return 0;
+    else
+        return 1;
+}
+
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_little_endian_double=yes
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+ac_cv_little_endian_double=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+fi
+
+{ echo "$as_me:$LINENO: result: $ac_cv_little_endian_double" >&5
+echo "${ECHO_T}$ac_cv_little_endian_double" >&6; }
+if test "$ac_cv_little_endian_double" = yes
+then
+
+cat >>confdefs.h <<\_ACEOF
+#define DOUBLE_IS_LITTLE_ENDIAN_IEEE754 1
+_ACEOF
+
+fi
+
+{ echo "$as_me:$LINENO: checking whether C doubles are big-endian IEEE 754 binary64" >&5
+echo $ECHO_N "checking whether C doubles are big-endian IEEE 754 binary64... $ECHO_C" >&6; }
+if test "${ac_cv_big_endian_double+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+
+if test "$cross_compiling" = yes; then
+  ac_cv_big_endian_double=no
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <string.h>
+int main() {
+    double x = 9006104071832581.0;
+    if (memcmp(&x, "\x43\x3f\xff\x01\x02\x03\x04\x05", 8) == 0)
+        return 0;
+    else
+        return 1;
+}
+
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_big_endian_double=yes
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+ac_cv_big_endian_double=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+fi
+
+{ echo "$as_me:$LINENO: result: $ac_cv_big_endian_double" >&5
+echo "${ECHO_T}$ac_cv_big_endian_double" >&6; }
+if test "$ac_cv_big_endian_double" = yes
+then
+
+cat >>confdefs.h <<\_ACEOF
+#define DOUBLE_IS_BIG_ENDIAN_IEEE754 1
+_ACEOF
+
+fi
+
+# Some ARM platforms use a mixed-endian representation for doubles.
+# While Python doesn't currently have full support for these platforms
+# (see e.g., issue 1762561), we can at least make sure that float <-> string
+# conversions work.
+{ echo "$as_me:$LINENO: checking whether C doubles are ARM mixed-endian IEEE 754 binary64" >&5
+echo $ECHO_N "checking whether C doubles are ARM mixed-endian IEEE 754 binary64... $ECHO_C" >&6; }
+if test "${ac_cv_mixed_endian_double+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+
+if test "$cross_compiling" = yes; then
+  ac_cv_mixed_endian_double=no
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+#include <string.h>
+int main() {
+    double x = 9006104071832581.0;
+    if (memcmp(&x, "\x01\xff\x3f\x43\x05\x04\x03\x02", 8) == 0)
+        return 0;
+    else
+        return 1;
+}
+
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_mixed_endian_double=yes
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+ac_cv_mixed_endian_double=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+fi
+
+{ echo "$as_me:$LINENO: result: $ac_cv_mixed_endian_double" >&5
+echo "${ECHO_T}$ac_cv_mixed_endian_double" >&6; }
+if test "$ac_cv_mixed_endian_double" = yes
+then
+
+cat >>confdefs.h <<\_ACEOF
+#define DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754 1
+_ACEOF
+
+fi
+
+# The short float repr introduced in Python 3.1 requires the
+# correctly-rounded string <-> double conversion functions from
+# Python/dtoa.c, which in turn require that the FPU uses 53-bit
+# rounding; this is a problem on x86, where the x87 FPU has a default
+# rounding precision of 64 bits.  For gcc/x86, we try to fix this by
+# using inline assembler to get and set the x87 FPU control word.
+if test "$GCC" = yes && test -n "`$CC -dM -E - </dev/null | grep i386`"
+then
+    # Check that it's okay to use gcc inline assembler to get and set
+    # x87 control word.  It should be, but you never know...
+    { echo "$as_me:$LINENO: checking whether we can use gcc inline assembler to get and set x87 control word" >&5
+echo $ECHO_N "checking whether we can use gcc inline assembler to get and set x87 control word... $ECHO_C" >&6; }
+    cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+      unsigned short cw;
+      __asm__ __volatile__ ("fnstcw %0" : "=m" (cw));
+      __asm__ __volatile__ ("fldcw %0" : : "m" (cw));
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+  have_gcc_asm_for_x87=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	have_gcc_asm_for_x87=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+    { echo "$as_me:$LINENO: result: $have_gcc_asm_for_x87" >&5
+echo "${ECHO_T}$have_gcc_asm_for_x87" >&6; }
+    if test "$have_gcc_asm_for_x87" = yes
+    then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_GCC_ASM_FOR_X87 1
+_ACEOF
+
+    fi
+fi
 
 # Detect whether system arithmetic is subject to x87-style double
 # rounding issues.  The result of this test has little meaning on non
@@ -23327,6 +23613,13 @@ _ACEOF
 
 fi
 
+# ************************************
+# * Check for mathematical functions *
+# ************************************
+
+LIBS_SAVE=$LIBS
+LIBS="$LIBS $LIBM"
+
 # Multiprocessing check for broken sem_getvalue
 { echo "$as_me:$LINENO: checking for broken sem_getvalue" >&5
 echo $ECHO_N "checking for broken sem_getvalue... $ECHO_C" >&6; }

configure.in

@@ -3240,12 +3240,107 @@ else AC_MSG_ERROR([proper usage is --with-libc=STRING])
 fi],
 [AC_MSG_RESULT(default LIBC="$LIBC")])
 
-# ************************************
-# * Check for mathematical functions *
-# ************************************
+# **************************************************
+# * Check for various properties of floating point *
+# **************************************************
 
-LIBS_SAVE=$LIBS
-LIBS="$LIBS $LIBM"
+AC_MSG_CHECKING(whether C doubles are little-endian IEEE 754 binary64)
+AC_CACHE_VAL(ac_cv_little_endian_double, [
+AC_TRY_RUN([
+#include <string.h>
+int main() {
+    double x = 9006104071832581.0;
+    if (memcmp(&x, "\x05\x04\x03\x02\x01\xff\x3f\x43", 8) == 0)
+        return 0;
+    else
+        return 1;
+}
+],
+ac_cv_little_endian_double=yes,
+ac_cv_little_endian_double=no,
+ac_cv_little_endian_double=no)])
+AC_MSG_RESULT($ac_cv_little_endian_double)
+if test "$ac_cv_little_endian_double" = yes
+then
+  AC_DEFINE(DOUBLE_IS_LITTLE_ENDIAN_IEEE754, 1,
+  [Define if C doubles are 64-bit IEEE 754 binary format, stored
+   with the least significant byte first])
+fi
+
+AC_MSG_CHECKING(whether C doubles are big-endian IEEE 754 binary64)
+AC_CACHE_VAL(ac_cv_big_endian_double, [
+AC_TRY_RUN([
+#include <string.h>
+int main() {
+    double x = 9006104071832581.0;
+    if (memcmp(&x, "\x43\x3f\xff\x01\x02\x03\x04\x05", 8) == 0)
+        return 0;
+    else
+        return 1;
+}
+],
+ac_cv_big_endian_double=yes,
+ac_cv_big_endian_double=no,
+ac_cv_big_endian_double=no)])
+AC_MSG_RESULT($ac_cv_big_endian_double)
+if test "$ac_cv_big_endian_double" = yes
+then
+  AC_DEFINE(DOUBLE_IS_BIG_ENDIAN_IEEE754, 1,
+  [Define if C doubles are 64-bit IEEE 754 binary format, stored
+   with the most significant byte first])
+fi
+
+# Some ARM platforms use a mixed-endian representation for doubles.
+# While Python doesn't currently have full support for these platforms
+# (see e.g., issue 1762561), we can at least make sure that float <-> string
+# conversions work.
+AC_MSG_CHECKING(whether C doubles are ARM mixed-endian IEEE 754 binary64)
+AC_CACHE_VAL(ac_cv_mixed_endian_double, [
+AC_TRY_RUN([
+#include <string.h>
+int main() {
+    double x = 9006104071832581.0;
+    if (memcmp(&x, "\x01\xff\x3f\x43\x05\x04\x03\x02", 8) == 0)
+        return 0;
+    else
+        return 1;
+}
+],
+ac_cv_mixed_endian_double=yes,
+ac_cv_mixed_endian_double=no,
+ac_cv_mixed_endian_double=no)])
+AC_MSG_RESULT($ac_cv_mixed_endian_double)
+if test "$ac_cv_mixed_endian_double" = yes
+then
+  AC_DEFINE(DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754, 1,
+  [Define if C doubles are 64-bit IEEE 754 binary format, stored
+   in ARM mixed-endian order (byte order 45670123)])
+fi
+
+# The short float repr introduced in Python 3.1 requires the
+# correctly-rounded string <-> double conversion functions from
+# Python/dtoa.c, which in turn require that the FPU uses 53-bit
+# rounding; this is a problem on x86, where the x87 FPU has a default
+# rounding precision of 64 bits.  For gcc/x86, we try to fix this by
+# using inline assembler to get and set the x87 FPU control word.
+if test "$GCC" = yes && test -n "`$CC -dM -E - </dev/null | grep i386`"
+then
+    # Check that it's okay to use gcc inline assembler to get and set
+    # x87 control word.  It should be, but you never know...
+    AC_MSG_CHECKING(whether we can use gcc inline assembler to get and set x87 control word)
+    AC_TRY_COMPILE([], [
+      unsigned short cw;
+      __asm__ __volatile__ ("fnstcw %0" : "=m" (cw));
+      __asm__ __volatile__ ("fldcw %0" : : "m" (cw));
+    ],
+    [have_gcc_asm_for_x87=yes], [have_gcc_asm_for_x87=no])
+    AC_MSG_RESULT($have_gcc_asm_for_x87)
+    if test "$have_gcc_asm_for_x87" = yes
+    then
+        AC_DEFINE(HAVE_GCC_ASM_FOR_X87, 1,
+        [Define if we can use gcc inline assembler to get and set x87 control word])
+    fi
+fi
 
 # Detect whether system arithmetic is subject to x87-style double
 # rounding issues.  The result of this test has little meaning on non
@@ -3284,6 +3379,13 @@ then
   [Define if arithmetic is subject to x87-style double rounding issue])
 fi
 
+# ************************************
+# * Check for mathematical functions *
+# ************************************
+
+LIBS_SAVE=$LIBS
+LIBS="$LIBS $LIBM"
+
 # Multiprocessing check for broken sem_getvalue
 AC_MSG_CHECKING(for broken sem_getvalue)
 AC_CACHE_VAL(ac_cv_broken_sem_getvalue,

pyconfig.h.in

@@ -18,6 +18,18 @@
 /* Define if you have the Mach cthreads package */
 #undef C_THREADS
 
+/* Define if C doubles are 64-bit IEEE 754 binary format, stored in ARM
+   mixed-endian order (byte order 45670123) */
+#undef DOUBLE_IS_ARM_MIXED_ENDIAN_IEEE754
+
+/* Define if C doubles are 64-bit IEEE 754 binary format, stored with the most
+   significant byte first */
+#undef DOUBLE_IS_BIG_ENDIAN_IEEE754
+
+/* Define if C doubles are 64-bit IEEE 754 binary format, stored with the
+   least significant byte first */
+#undef DOUBLE_IS_LITTLE_ENDIAN_IEEE754
+
 /* Define if --enable-ipv6 is specified */
 #undef ENABLE_IPV6
 
@@ -240,6 +252,10 @@
 /* Define to 1 if you have the `gamma' function. */
 #undef HAVE_GAMMA
 
+/* Define if we can use gcc inline assembler to get and set x87 control word
+   */
+#undef HAVE_GCC_ASM_FOR_X87
+
 /* Define if you have the getaddrinfo function. */
 #undef HAVE_GETADDRINFO