Move HOST_LONG_BITS from qemu-common.h to qemu/osdep.h

qemu-common.h should only be included by .c files. Its file comment
explains why: "No header file should depend on qemu-common.h, as this
would easily lead to circular header dependencies."

One of the reasons for headers to include it is HOST_LONG_BITS. Move
that to its more natural home qemu/osdep.h, to facilitate removing
these ill-advised includes later on.

This also lets us use HOST_LONG_BITS in bswap.h instead of duplicating
its definition there to avoid cyclic inclusion.

Backports commit a8139632161d7546218b696cada0a4f64cc78fb7 from qemu

qemu/include/qemu-common.h

@@ -24,16 +24,6 @@
 #define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR)
 
 #include "unicorn/platform.h"
-
-/* HOST_LONG_BITS is the size of a native pointer in bits. */
-#if UINTPTR_MAX == UINT32_MAX
-# define HOST_LONG_BITS 32
-#elif UINTPTR_MAX == UINT64_MAX
-# define HOST_LONG_BITS 64
-#else
-# error Unknown pointer size
-#endif
-
 #include "qemu/bswap.h"
 
 /* FIXME: Remove NEED_CPU_H.  */

qemu/include/qemu/bswap.h

@@ -415,11 +415,9 @@ static inline void stfq_be_p(void *ptr, float64 v)
 
 static inline unsigned long leul_to_cpu(unsigned long v)
 {
-    /* In order to break an include loop between here and
+#if HOST_LONG_BITS == 32
-       qemu-common.h, don't rely on HOST_LONG_BITS.  */
-#if ULONG_MAX == UINT32_MAX
     return le_bswap(v, 32);
-#elif ULONG_MAX == UINT64_MAX
+#elif HOST_LONG_BITS == 64
     return le_bswap(v, 64);
 #else
 # error Unknown sizeof long

qemu/include/qemu/osdep.h

@@ -115,6 +115,15 @@
 #define TIME_MAX LONG_MAX
 #endif
 
+/* HOST_LONG_BITS is the size of a native pointer in bits. */
+#if UINTPTR_MAX == UINT32_MAX
+# define HOST_LONG_BITS 32
+#elif UINTPTR_MAX == UINT64_MAX
+# define HOST_LONG_BITS 64
+#else
+# error Unknown pointer size
+#endif
+
 #ifndef MIN
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
 #endif