Avoid __BIG_ENDIAN__

This is pre-defined by GCC on _some_ platforms. Here, we don't want GCC
pre-defined setting but instead want our own setting to test both little
and big-endian settings.

Author: tautschnig

regression/cbmc/Pointer_array7/big-endian.desc

@@ -1,6 +1,6 @@
 CORE new-smt-backend
 main.c
---big-endian -D__BIG_ENDIAN__
+--big-endian -DUSE_BIG_ENDIAN
 ^EXIT=0$
 ^SIGNAL=0$
 ^VERIFICATION SUCCESSFUL$

regression/cbmc/Pointer_array7/main.c

@@ -1,13 +1,13 @@
 #include <assert.h>
 #include <stdint.h>
 
-#if !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
+#if !defined(USE_LITTLE_ENDIAN) && !defined(USE_BIG_ENDIAN)
 
 #  if defined(__avr32__) || defined(__hppa__) || defined(__m68k__) ||          \
     defined(__mips__) || defined(__powerpc__) || defined(__s390__) ||          \
     defined(__s390x__) || defined(__sparc__)
 
-#    define __BIG_ENDIAN__
+#    define USE_BIG_ENDIAN
 
 #  endif
 
@@ -21,7 +21,7 @@ int main()
   uint8_t *y = (uint8_t *)x;
   uint16_t z = *((uint16_t *)(y + 1));
 
-#ifdef __BIG_ENDIAN__
+#ifdef USE_BIG_ENDIAN
   assert(z == 256u);
 #else
   assert(z == 512u);

regression/cbmc/Pointer_array7/test.desc

@@ -1,6 +1,6 @@
 CORE new-smt-backend
 main.c
---little-endian -D__LITTLE_ENDIAN__
+--little-endian -DUSE_LITTLE_ENDIAN
 ^EXIT=0$
 ^SIGNAL=0$
 ^VERIFICATION SUCCESSFUL$

regression/cbmc/Struct_Bytewise1/struct_bytewise.c

@@ -1,18 +1,3 @@
-// Determine endianness.
-// Follows http://wiki.debian.org/ArchitectureSpecificsMemo
-
-#if !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
-
-#if defined(__avr32__) || defined(__hppa__)    || defined(__m68k__) || \
-    defined(__mips__)  || defined(__powerpc__) || defined(__s390__) || \
-    defined(__s390x__) || defined(__sparc__)
-
-#define __BIG_ENDIAN__
-
-#endif
-
-#endif
-
 typedef struct my_struct
 {
   // We hope these are 32 bit each on all architectures,
@@ -37,7 +22,7 @@ int main()
   logAppl.b=0x01000002;
   CopyBuffer((unsigned char *)&logAppl);
 
-  #ifdef __BIG_ENDIAN__
+#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
   assert(arrayTmp[0]==0);
   assert(arrayTmp[1]==0);
   assert(arrayTmp[2]==0);